The thing is, he goes off during songs, not just during extended solos.? In fact, when I saw the band in Cleveland in '02 he left the stage usually once or more per song, probably to get oxygen.? It is very annoying, mainly due to the frequency of his trips backstage.
Is he still doing this?? Everyone in this thread seems to be saying that he's leaving during extended solos, but I worry that like last time he'll be on and off stage a couple dozen times per night.? Really, that was the one characteristic of the '02 show that prevented it from being a great show.?
He has made trips backstage during songs since they were big enough to have a backstage. Despite the theories about him using oxygen, my guess is that he doesn't feel really comfortable being out in front with nothing to do during long guitar solos.