The 70s-90s was basically the boom of international stars, with a highly limited media ventures, so everyone with a TV would be aware of them, at least in the western world.

From 2000s, culture has been more diluted across the medias.

Just that it is mostly uniquely millennials right now... Sure every generation gets their time, but their comment is about whose time it is now

I happen to think Western music and culture peaked through those 3 decades though. I'm talking more film, TV and music not literature.

So it's the passing of real talent without replacement. I think we live in a pretty dead culture now. Just my opinion of course.