Hard to buy new music when there's so much old music I missed and am just now discovering.
exactly so!
after all, I'd say the actual problem is about those who, from a certain age and on, happen to always listen to the same few songs/artists and, on the other side, those who try to listen to a lot of different songs/artists and always adding more and more... and this is regardless of when such music was actually made... that's mostly about the actual tastes of any of us.
It's true that, when we were teen, it was obvious to listen (or to also listen) to the current music but getting more adult it's typical that your tastes get more specialized and then, if you are a true passionate, you try to dig into certain music eras in particular.
Personally, since the very end of the 80s, I disliked how the current music was evolving and I can think about very few albums/artists I love from post-1988 era so I prefer to stick to the 1967-1987 time range which is, by far, my own favourite and where yI can find lots of different kinds of music to listen to different stuff for the rest of my life.
In the meanwhile, the teens will enjoy the current stuff as it always happened.