Movie thoughts: Who deserves to be famous?

My husband watches a lot of Law and Order (which is easy to do because it seems to run on one channel or another nearly round the clock). Last night, as I was heading to bed, he turned on USA and there was David Keith appearing as a guest on a recent episode of Criminal Intent. I was really sad to see him (though there were two consolations -- he looked great, and CI is at least a decent show). My friend Mary and I fell madly in love with David when we saw him in Brubaker, a 1980 Robert Redford vehicle based on the true story of a prison reformer in the 1960s south. Then, in 1982, David broke everyone's heart as Richard Gere's sidekick in An Officer and a Gentleman. He had a respectable career for awhile (and still works regularly), but never reached the stratosphere that his talents and charisma warranted. My friend Sue recently commented that Aidan Quinn never became the superstar he deserved either. What determines this progression? Why do some performers break out and others fade into obscurity (or second tier status)? I'm not a fan of Tom Cruise (apologies to my friend Suzanne), and when I saw him in Eyes Wide Shut, it confirmed my suspicions that his talents are limited. He's even made a few bombs, but his career trajectory seems failure-proof. Why is that? Aidan Quinn has made some offbeat choices, so a performer's own preferences play a part. Certainly looks are a factor and that whole Q score thing. Also how much they seek the limelight. Maybe some just have crappy agents. And maybe some don't care about being famous -- some actors are quite happy to live in Montana or South Carolina and actually have some balance in their lives. But even taking that into consideration, with some notable exceptions (Robert DeNiro, for example), the level of success does seem to be curiously unconnected to the level of talent.