The problem is that he will need to lose a LOT of time before anybody's willing to let him go - the GC candidates won't let Evans go if he's only 5 minutes back, and even if he's more than that, we've seen from Cancellara last year that a rider of Evans' calibre has to be so distant as to be GC-irrelevant (as Pellizotti was last year) to be welcome in a break. I think Evans is too driven to deliberately lose that time à la Moncoutié or Cunego in search of a KOM or stage win, and so he's doomed to another year of being 'one of the heads of state' without ever taking the top prize.
I always wonder if Evans actually feels safer when he has an excuse for not winning. The only problem with this is that it makes him come across as a whiner so that even when he does have a case (the terrible luck with the puncture in the Vuelta, or Gesink blocking him in the chase for the line on Xorret del Catí) people roll their eyes and go 'yea yea, whatever, Cadel'. I also suspect that, much like Britain and America, outside of the dedicated cycling community the Tour de France is all that's known of the calendar, and Cadel has focused all his effort on the Tour for that reason, to disastrous effect on his palmarès, which really ought to be better than it is. And I'm sure he knows that. After all, Denis Menchov has 3 GTs, and Cadel Evans has 0. Is Menchov really THAT much better?