Not everybody needs to know the same things.
It’s not essential information, but a basic awareness of popular culture never hurt. I’m not even a Sinatra guy, but I know who he is and what his signature tune was.
The old joke about people who think Paul McCartney’s first band was Wings is being replaced by “Paul who?”Yeah but I’m sure you don’t know stuff that people thirty years older than you might.
Maybe? Depends on the subject. But that’s what old movies, documentaries, and history books are for. Not to mention that internet thing the kids seem to like.
I don’t need to know about Flash Gordon or Buck Rogers to enjoy Star Wars, but it deepens my enjoyment of it.
For some people these days anything prior to 2000 might as well be a hundred years ago.