I don't know if "Stadium Rock" or even "Arena Rock" will be around 20 years from now, but I do think some artists have staying power - they might be playing theaters as opposed to stadiums and arenas, but there are a few out there. Peter Buck of R.E.M. recently said rock today is sort of like jazz in the '60s - there's a lot of great things going on out there, it just isn't mainstream. I think hip-hop has basically taken over the mainstream.
That being said, there are a few bands/artists that I think will be around for a while:
Beck
Radiohead
Damon Albarn (Whether it's with Blur or Gorillaz, I think he has staying power because he's not afriad to try new things and he's very clever)
Wilco/Jeff Tweedy
The Arcade Fire
Although he's been around a while, I still see Prince selling out arenas for the next decade at least. He sold out two night at the American Airlines Center here in Dallas a couple of years ago
Oasis just had a great comeback in America - Heck, they sold out Madison Square Garden
I see R.E.M. reuniting with original drummer Bill Berry in a couple of years and selling out arenas all over the U.S. - Their music has a timeless quality to it, and I just think they are going through a lull in popularity right now. I can easily see them having a major comeback. (Like Prince did a couple of years ago)
I don't know what's going to happen with Coldplay.
I think Travis/Fran Healey are going to continue making great records, and there will be a cult of people still listening.
I'm beginning to like Keane more and more these days, and I have high hopes for their new album, but I don't know what kind of staying power they have. - but it's sort of like what Peter Buck was saying - they are a great band, just not massively popular right now.
I'm afraid Franz Ferdinand, The Killers, The Scissor Sisters, and all of those other retro bands are going to be remembered only for a couple of hit singles, which is a shame because they wrote such great, catchy songs. I really like "Do You Want To" by Franz, but it just seems more of the same new wave/retro music which was already on their debut album.




