Go See Jimmy @ Vic's Drum Shop

Jimmy Chamberlin and Umphrey's McGee

Kicking off the music portion of the Groupon Arts Collaboration Series, here's Jimmy with Umphrey's McGee at their recent performance;

Question

I don't quite understand why it seems at times to be accepted by 'a general listening public' [e.g. not musicians & certainly not drummers] that whilst the rest of a given band plays note for pretty much note what a song is [as defined by a recorded version of it ] - whilst the drummer plays what amounts to degrading, say 'Asturias', into power chords (with half the strings missing) and yet that, that seems to be OK with them?

Whyyyyy...