I don't know the reasons, but it's a hill I am willing to die on

The reason is technology. Current generations have unlimited access to anything they want to listen to. And advances in music creation software and accessibility of recording devices mean there are also exponentially more musicians to listen to. They're so overwhelmed by keeping up with present releases, and the ability to only listen to exactly what they want to, that there quite literally isn't enough time (or willingness) to dive into the past, other than a highly curated, select few bands.

Back in the day you learned about older music because you had to listen to your parents music, whether you liked it or not. That's all that was laying around. And tv shows and movies were dictated by what happened to be on local tv - often shows literally decades old. All the tv shows I remember growing up with were already old as shit by the time I was watching them as a kid. That just doesn't happen now.

And when you got to your teenage years, old enough to start buying your own music, that's when you could start developing your own, limited collection, shelling out $15 for a tape or CD, or finding friends to copy music from.

Nowadays a 7 year old could pop onto their parent's Spotify account and drop into a rabbit hole where they never have to listen to anything older than them for the rest of the their life. Where they're now infinite scrolling through the newest (to the minute, in some cases) uploads from YouTubers and TikTokers, we were spending that time listening to music or watching movies from the past.