Disco music AIN'T classical music. Classical music is still listened to because it is tried and tested, that is, still being listened to and played all over the planet.
Side-note: the Chinese are big into opera these days, thanks to the Great One, Luciano Pavarotti, who introduced opera to the Chinese. The crowds applauded LOUDLY whenever Pavarotti hit The High Note. Also, there are now Chinese tenors who appear in world-wide opera. Talk about WEIRD to look at...the famous operas are in Italian and German (with some in French and other languages). WEIRD, weird, weird.
The funny thing that I’ve observed is, going to a lot of parties with people in their mid-40s is that once they put on some 70s disco, everybody immediately starts dancing....and I would suspect most of those people are the people who hated it back then. Like it or not, it was the soundtrack of our lives back then.
I can hardly think of any popular music of the rock era that will be listened to as long as the classics. And I mean the real classics, now, the Mozarts, Beethovens, Bachs. At best Sinatra (yes, I realize he’s anchored in a previous era), Elvis, the Beatles, and Michael Jackson. But this is an unfair comparison. It’s like setting DaVinci beside doddles in a magazine ad. Classical music is high art, though often with great popular appeal. Rock and roll is all popular appeal.