Yeah he really hurt Landis on that climb and LA did his best to rub it in. Levi hung with TD for the most part. IMHO Floyd isn't the big story when it comes to GC Levi is. Floyd gets the hype because of his split with LA but Levi has dropped Floyd on every climb that matters from the TdG to the TdF.
Tom isn't a spring chicken in age but as for his years on the bike he's still very young. He has the talent but he seems a bit fragile. Disco had some big plans for him at this years Giro and his knee flared up and that was that.
The problem is not going to be if there are some up and coming American riders, there are some very talented guys coming through the ranks. The problem is that none of them will be as dominating as LA. He's set the bar so high for the casual American cycling fan that winning the TdF 6 times would seem like a failure. Unlike Euro cycling fans who would see a top five as a real accomplishment American sports fans look at second place as the first looser.