I think it's much easier for the sound guys to get the sound right for a band like Pink Floyd. Long drawn out notes are so much easier to sound easy on the ears.
Don't get me wrong, I love listening to my Dark Side SACD and I respect the hell out of Floyd and think they are amazing musicians. It's just that if you had those same guys trying to play something faster and heavier it would be hard to make it sound as good live.
I kind of have the same opinion about speakers. If you play an audiophile type of song, like Keith Don't Go for example, that song is going to sound great on all kinds of speakers.
Throw on something a little more challenging like Jambi, Learning to Live, Blackwater Park, Call of Ktulu, Love?, Black No. 1, Light up the Sky, The Wizard, What's Next to the Moon, etc. and you find out real quick the speakers that will cry uncle.
Getting back to concerts, I do agree with Nathan - most concerts I have been to have been a let down. Half way through the first song that realization of, "oh, so this is what these guys sound like live..... hmmm better get some more beer...."