Even if you’re a Traditional Latin Mass type, this is true. Some music that once sounded revolutionary now sounds tired. Or it’s been done so many times that people tire of singing of it. Or you’ve hit a nice patch of inertia and want to stick to a smaller song set. Either way, it’s a practical problem that’s easily solved.
I thought about this one day when I finished my Masses and was followed by a “contemporary” group at the last Mass. Their plans included doing “Awesome God” (more thoughts about that here) and, if memory serves, “I Could Sing of Your Love Forever.”
We could debate over whether those pieces should be done at Mass, but my concern is more this: over the last many years, plenty of “contemporary,” orthodox, thematically sensible, thoroughly Catholic music has been churned out, and though plenty of it is rubbish, still other pieces are very strong. They deserve evaluation to see whether they could fit into a church’s plans.
But, like I said, this is true even in TLMs. Language changes, and sometimes those old hymns have language that sounds terrible today. (Example A: from “O Come, All Ye Faithful,” the translation of one line as “Lo, He abhors not the virgin’s womb”). Or they express ideas that have either fallen out of favor or aren’t a good idea to do today. Though the Mass is, of course, timeless, the language isn’t necessarily the same way.