You can't make a rule out of an exception. I can dance to it just as well as any other music, just think Elaine on Seinfeld. I can hum the music because I'm a musician, but it's often not easy, which line to choose. In my mind when you think or focus or concentrate on the music you get absorbed into the music and each listen brings out different things, you hear other instruments, tempos, sounds, harmonies, etc even decades later. I literally get lost in the music. It's not such much mathematical type of focus or listening. But that does not fit the majority either.
And if you want me to play 2112 I'm going to need more than 50 bucks and a beer. Let's face it most of us can show up at a gig and "pull it off" but not if your playing Rush, especially old school Rush. So yeah it is hard to play, because you also have to find 3 or 4 people interested and able to put the time in. You are a highly skilled musician who wants to put the time in. And I think (no proof) that musicians (skilled and wanna be's) make up a huge part of the audience for Prog and other similar genre like fusion.
It seems some think it's all or nothing, but there is still a bunch out there keeping it popular enough, it doesn't have to be the very top. But each generation does take something different to the very top for some period of time, and 30 or 50 years later will have the same conversation we are having today.
And it's a great conversation.