One change our parish recently implemented (where non-singing is epidemic) was printing out the music on a worship aid. So it’s literally right there. No thumbing through books, no numbers posted anymore - you just sing what’s on the paper right in front of you.
Since I am a convert, I still don’t reliably know a lot of the “standards” even though I can frequently do the refrains and/or can hum along with the tune. I can’t always hold the paper because my arms are full of kid. I still notice that my husband and I are usually the only people I can hear singing near us, and it’s not because we drown everybody out.
We’re blessed with a great music ministry, and they work really hard to try to get the congregation involved, and will do brief lessons sometimes on specific things before Mass. But if you’re the kind of person who shows up late…which we have a lot of…you’re going to miss that.
Even so, the music at Mass is so beautiful sometimes it makes me cry. I am not educated in music but I know it can be incredibly moving when done well and I definitely understand it as a form of prayer.