Agree with this post almost verbatim. I suspect that as many folks get older, they feel like there's stagnation when in reality there may not be. We just tend to focus on the stuff we like/liked, often to the exclusion of newer things. Because of that we don't see the firehose of "new" that is continuously pouring out.
I'm 58, and enjoy music, movies, shows, theater, and the like. I like to think I'm on top of things, but I'm really not. My daughter and son-in-law that live here locally sing along with songs passionately, yet in many cases they're songs that I've never heard of before. For them it's a rich time I think. Same with our kids that live in other states.
I actually like that, and it helps me realize culture kept moving along, and I'm simply not in the target age demographic for the most part anymore. I'm fine with that, and still like what I like, some new, some old. But I know it all continues.