Steubenville, Lifeteen, etc

your music has created an atmosphere conducive to their meditation.

For a real example to consider and evaluate, this is the most recent release from OCP in the P&W genre, or what it considers to be P&W. The "artist" is a guy whom OCP is really, really pushing hard trying to make him their in-house Matt Maher:

That's why P&W in many circumstances would not be a good choice for music at Mass. Under some pastoral circumstances its use could be justified, but I think only as a temporary concession while the barge is steered in a different direction.

it ought to be maintained as a concession while being slowly retired.

You can't suddenly eliminate the music that people know and love at Mass without alienating and upsetting a significant number of people.

Even then, the pastor may be transferred before you accomplish much.

An aside: When we're speaking of the 'personalist' element in contemporary music, does that include the technical side as well as the emotional side? Because what I've noticed in singing from the WLP recently is just how virtuosic a lot of the entries are. The irregular rhythms, the word underlay changing from verse to verse, a lot of non-intuitive jumps - it's not that the music itself is bad per se, they just don't make sense as congregational pieces. (I'm probably bringing nothing new to the table here.)

This is indeed problematic. In their defense, they are presented in a way that is typically in accord with traditional hymnody (musically speaking; something that can't be said for P&W). But there is some merit to your observation, certainly. There is a fine degree of separation however; these other works are readily adapted to their new task in a way that isn't at odd with the larger tradition of hymnody. P&W music cannot claim the same. Stylistically it imitates secular music, is played on instruments which, if we wish to be technical, are only suited to secular music and were banned by Pius X (although this is no longer observed), and cannot be dressed up in any way that makes it seem like any form of well-established liturgical music.

As for the latter half of this observation regarding Bach & Mozart, their liturgical music was conceived as liturgical music. It happened to be orchestral, so it bears obvious similarities to their other work. I'm not sure how it could not when one employs a full orchestra to make the grandest musical offering possible. But in the sense of Gebrauchsmusik, it is liturgical music—so conceived—from the get-go. You'll also note that they didn't write music using street bands as ensembles. It was high-art music, not common-man music.

When I write music for Mass, I don't expect it to also pull double-duty on the radio as easy-listening music once the pews are empty. I also try not to write pedestrian music (read: quotidian in style and essence; 'pedestrian' is not intended as a derogatory term). Is it the same in P&W culture? I don't think it is.

62. Musical instruments can be very useful in sacred celebrations, whether they accompany the singing or whether they are played as solo instruments.

"The pipe organ is to be held in high esteem in the Latin Church, since it is its traditional instrument, the sound of which can add a wonderful splendor to the Church's ceremonies and powerfully lift up men's minds to God and higher things.

"The use of other instruments may also be admitted in divine worship, given the decision and consent of the competent territorial authority, provided that the instruments are suitable for sacred use, or can be adapted to it, that they are in keeping with the dignity of the temple, and truly contribute to the edification of the faithful."

high-art music, not common-man music

A standard I would propose instead - that works of music have a teleos, and that the teleos need to be that it is designed to be liturgical music and designed for worship of God.

With regard to compositions of liturgical music, I make my own the “general rule” that St Pius X formulated in these words: The more closely a composition for church approaches in its movement, inspiration and savour the Gregorian melodic form, the more sacred and liturgical it becomes; and the more out of harmony it is with that supreme model, the less worthy it is of the temple”. It is not, of course, a question of imitating Gregorian chant but rather of ensuring that new compositions are imbued with the same spirit that inspired and little by little came to shape it.

Absent a ban from the USCCB on the instruments commonly used in praise and worship, I think it is going to be difficult to definitively claim they are not appropriate for the liturgy, particularly when they are in common use throughout the country. Certainly the USCCB is not ignorant that the piano and guitar are commonly played liturgically.

While I understand your thought, I would argue that it is contrary to the teachings of the church. The first would be from Vatican II which said that chant had "pride of place." This means that we should do chant unless it is not possible (Ex: a particular piece is too difficult for the singers, but a lot of the propers have simplified versions).

116. The Church acknowledges Gregorian chant as specially suited to the Roman liturgy: therefore, other things being equal, it should be given pride of place in liturgical services.

But other kinds of sacred music, especially polyphony, are by no means excluded from liturgical celebrations, so long as they accord with the spirit of the liturgical action, as laid down in Art. 30.

The “pride of place” given to Gregorian chant by the Second Vatican Council is modified by the important phrase “other things being equal.” These “other things” are the important liturgical and pastoral concerns facing every bishop, pastor, and liturgical musician.

119. In certain parts of the world, especially mission lands, there are peoples who have their own musical traditions, and these play a great part in their religious and social life. For this reason due importance is to be attached to their music, and a suitable place is to be given to it, not only in forming their attitude toward religion, but also in adapting worship to their native genius, as indicated in Art. 39 and 40.

119. In certain parts of the world, especially mission lands, there are peoples who have their own musical traditions, and these play a great part in their religious and social life. For this reason due importance is to be attached to their music, and a suitable place is to be given to it, not only in forming their attitude toward religion, but also in adapting worship to their native genius, as indicated in Art. 39 and 40.

Does this justify foregoing normal liturgical music in favor of music that imitates all the secular music on the radio in America? We haven't been a missionary territory for 250 years and our literacy rate is extremely high, even in the lowest strata of society. This would seem to indicate to me that no concession needs to continue to be made on this front.

In certain parts of the world, especially mission lands, there are peoples who have their own musical traditions, and these play a great part in their religious and social life.

In mission lands, there are peoples who have their own musical traditions, and these play a great part in their religious and social life.

If the "post-Christian secular West" is mission territory right now, that's the result of attempted collaboration with it -- that is, not being sufficiently authentic and insistent on what it means to be Catholic.

insistent on what it means to be Catholic

Using more secular idioms in an attempt to draw the secular world away from secularism is exactly what we're NOT supposed to do.

119. In certain parts of the world, especially mission lands, there are peoples who have their own musical traditions, and these play a great part in their religious and social life. For this reason due importance is to be attached to their music, and a suitable place is to be given to it, not only in forming their attitude toward religion, but also in adapting worship to their native genius, as indicated in Art. 39 and 40.

4. It is to be hoped that pastors of souls, musicians and the faithful will gladly accept these norms and put them into practice, uniting their efforts to attain the true purpose of sacred music, "which is the glory of God and the sanctification of the faithful."

(a) By sacred music is understood that which, being created for the celebration of divine worship, is endowed with a certain holy sincerity of form.

(b) The following come under the title of sacred music here: Gregorian chant, sacred polyphony in its various forms both ancient and modern, sacred music for the organ and other approved instruments, and sacred popular music, be it liturgical or simply religious.

Sacred music also carries out another task, that of bringing together Christian history: in the liturgy, Gregorian chant, polyphony, popular music and contemporary music resonate. It is as though, in that moment, there were all the past and present generations praising God, each with its own sensitivity. Not only that, but sacred music – and music in general – creates bridges, brings people closer, even the most distant; it knows no barriers of nationality, ethnicity, or skin colour, but involves everyone in a higher language, and always manages to bring together people and groups even from very different backgrounds. Religious music shortens distances, even between those brothers and sisters who sometimes do not feel they are close. For this reason, in each parish the singing group is a group where one encounters availability and mutual help.https://www.vatican.va/archive/hist_councils/ii_vatican_council/documents/vat-ii_instr_19670305_musicam-sacram_en.html

Does this justify foregoing normal liturgical music in favor of music that imitates all the secular music on the radio in America?

This person loves country and hates rap, this person loves classic rock and hates everything else, this person loves K-pop and hates country, etc.
That is one big reason that the music at church shouldn't sound like anything commercial or of a popular genre.

4b: Sub nomine musicae sacrae hic veniunt: cantus gregorianus, polyphonia sacra antiqua et moderna in suis diversis generibus, musica sacra pro organo et aliis admissis instrumentis, et cantus popularis sacer seu liturgicus et religiosus.

51. Popular religious song is to be highly recommended and promoted. By means of it, in fact, Christian life is filled with religious spirit and the minds of the faithful are elevated. Popular religious song has a place in all the solemnities of Christian life, whether in public or in the family, and even during the labors of daily life; but it has an even nobler part to play in all the .. pious exercises" performed inside and outside the church; and it is sometimes admitted in liturgical functions themselves, according to the norms set down in numbers 13-15.
52. So that popular religious songs may then accomplish their purpose, "it is necessary that they fully conform to the doctrine of the Catholic Faith, that they expound and explain it rightly, that they use simple language and simple melodies, that they be free of ostentatious and inane superfluity of words, and finally, even if they are short and catchy, that they contain a religious dignity and seriousness." (Musicae sacrae disciplina: AAS 48 [1956] 20.) The Ordinary must watch with care that these prescriptions be observed.
53. All those who are interested in the subject are urged to collect the popular religious songs, even the most ancient, which have been written or passed down by word of mouth, and to publish them for the use of the faithful, subject to the approval of the Ordinaries of places.