Jan rode the Giro for fitness, not with GC aspirations - that's well documented. Having to drop out on the second or third last mountain stage is no biggie and certainly not a mental blow. Don't forget that other than Armstrong, he's the best Tour rider by far of the 90s. Basso does not have a mental edge over Jan in that respect.
Remember, too, that while Basso rode very impressively in a very hard Giro, a lot of guys are training only for the Tour - it's going to be way harder to win. Ullrich aside, there's Landis, Leipheimer, Valverde, Evans (who we pass on his training rides twice a week going the other way), Kloden (meh), etc, etc, all who didn't ride the Giro…Basso and Ullrich will be two of the main contenders, but it's not just down to them, that's for sure. How about Boonen and McEwen fighting it out to see who wears green? Rasmussen might be in polka dots, but you won't see him on the podium. Vino? I'm sad to say his Tour looks doubtful unless he can find another ride…I hope he makes it there one way or another because I love watching him ride.