Thomas Day’s classic Why Catholics Can’t Sing: The Culture of Catholicism and the Triumph of Bad Taste has a lot of the answers. He puts it down to the Irish Catholic history.
It goes like this: the main English speaking Catholics to hit these shores were Irish. The Irish were persecuted by the English and had to worship in secret. They associated hymn singing with the hated Anglicans and Methodists. A kind of Irish non-hymn singing pride developed: “We’re Irish. We’re Catholic. We don’t sing hymns. They’re Protestant. They’re English. We’ll be damned if we sing.”
I think Day’s hypothesis is part of the formula, but there is more to it than that.
Speaking as a former Anglican I can say that the Anglicans have, over hundreds of years, built up a solid repertory of good hymns. Most Anglican congregations across England will all know the same, good fifty or sixty hymns. They love singing them. It is part of their worship and culture.
In the USA before Vatican II hymns were not part of the Mass. Catholics had no opportunity to develop a shared, nationwide repertory of hymns.
Then after V2 hymn singing was integrated into the Mass. Suddenly we were flooded with new hymns–most of which had banal lyrics, crappy folk music and trite sentiment. The Catholics didn’t sing the old hymns because they didn’t know them. In the meantime they were having lots of awful new songs shoved down their throat and they (quite rightly) didn’t bother singing them because they knew deep down that they were either unsingable or execrable.
The few songs that did become popular in one area of the country may not have become popular in other parts of the country. Therefore when Catholics turned up at a different part o the country in a different parish they had to learn all new hymns.
Furthermore. I have asked Catholic priests if they ever received any training at seminary in the tradition of hymnology, sacred music, chant or the proper way to choose hymns for liturgy. The answer has almost always been a resounding “No.”
So here we have it. The people don’t know the good old hymns. They don’t like singing the new crappy songs. (and who can blame them?) The priests don’t know the good old hymns. Then there is the ideological factor that many priests don’t want to get to know the good old hymns anyway because “They’re old fashioned” or “They have too many long words in them” or “they’re not cheerful enough” or “they’re Protestant”.
What’s to be done? First of all get a good hymnal like Worship which is fully Catholic, has good modern stuff in it as well as the good old hymns from the Anglican and Methodist traditions (theology adapted where necessary) Get a good organist (preferably a convert from Anglicanism) start teaching the children to sing good hymns. Choose a small repertoire of good hymns and use them again and again. Develop a decent choir who can sing the hymns beautifully.
Eventually the big ship will turn.