panyncor: I don't really " get " this thought experiment. If, for the sake of argument, we accept that people can mistakenly put an inferior band over a superior band now, I don't see why they would not be able to do that in a 100 years, or for that matter in a 1000, or 10000, or 100000 years. Naturally, in a million years folks should be advanced enough to see that PF is totally cooler than Beatles ;-).
According to some cosmologies, golden age is a time when arts, sciences and development of people is at its height, during silver age it is lower, during iron age it is extremely low. By that logic, both Beatles and Pink Floyd are musicians of our iron age. Therefore, people living in the next Golden age will poo-poo both Pink Floyd and Beatles and will only make minor distinction between them.
I will listen to Floyd because I like their songs that much better, and I'm still living here, in our sorry times ;-).