Great chat this.
I have definitely found that the things you really love come around less frequently as you age. And you see a lot of stuff that is clearly a retread of something from 20-30 years ago, and it’s easy to be cynical and jaded.
I wonder if this is not just a reduction in capacity to love music, but an active resistance to wanting to enjoy new things. Like when an artist has a 'change of direction’™ and their fans start to hate them. Maybe people link the sounds they loved in their youth to emotional experiences and want to cling on to them, like @bamnan says, because they can’t separate their liking for it from their memories of enjoying it.
On the other hand, people have been listening to Mozart for over 200 years and not getting sick of it. Maybe they got into it when they were young though.