This is in response to Ewan's comments in this thread, and yes, Caitlin, I will get around to another Star Wars post that will address your comments; don't give up hope.
I think that The Beatles break up is a key part of their legendary status. Like Seinfeld, they went out at the top of their game. Rather than dissapearing with a quiet whimper, slowly into the night, The Beatles went out with a crescendo, and a final crashing chord, not unlike the final notes in "A Day In The Life." However a part of me has always wondered what The Beatles might have done if they stayed together. I think the solo careers of Lennon and McCartney, and Harrison, were filled with further great works, and I doubt they would have become washed up, but rather I think it was a matter of those egos, esp. Lennon and McCartney, couldn't really fit into one band. They had become bigger than The Beatles.
As for Nirvana, I always wonder about that as well, and I think part of their status was that they burnt out so quickly. But the fact that they were in the spotlight for such a short time makes me wonder what we're missing. A lament for what might have been, if you will. Reminds me of the literary examples of Christopher Marlowe (Dr. Faustus, Tamburlaine) - whose plays were arguably as good as Shakespeare's - but whose plays were cut short when he was stabbed through the eye in a bar brawl. Or John Keats who died at age 24. What masterpieces did we lose when poor health cut short his amazing output? It's something I don't think we can ever know.
Then there's the further examples of Sting, Elvis Costello and Stevie Wonder. All I can do is quote Barry (Jack Black) in High Fidelity..."top five musical crimes perpetuated by Stevie Wonder in the 80s and 90s? Go... sub-question... is it in fact unfair to criticize a formerly great artist for his latter day sins, is it better to burn out or fade away? "
And with that the example of U2 becomes curious. They are arguably doing as good work now as they were in any era. They haven't really pandered to the youth demographic, nor are they merely an adult contemporary act (ie: Sting). It's really quite amazing the more I think about it. I'm hard pressed to come up with another example of it.
"Well, everybody wants to go forever
I just wanna burn up hard and bright
I just wanna be your firecracker"
- Ryan Adams, "Firecracker" from the album Gold