What I mean is, I think it's the college age kids that are buying most of the concert tickets. But I don't think the college kids are hip to DAvid Bowie these days. Try Dave Matthews, Phish, and other newere artists, epsecially those with a pseudo-jammy vibe. Or maybe the nu-metal stuff.
There are some classic acts that bring out the middle age crowd, such as Springsteen or the Eagles, but I don't think Bowie ever had nearly the popularity as those acts in America to begin with.