Well, that was certainly the case for years past. Remember the days when Mig was winning the Tour, and those races had nearly 200km of total TT km's. This year's Tour then should show, with it's low TT km's, that a climber is primed to win it. But we already suspect that climber will have the initials AC.
Basso looked very much like he was going to win a Tour before he got himself into trouble. Assuming he's as talented as we thought and it wasn't all doping, he may well win the Tour yet.
And he isn't the only Italian caught doping in recent years.
I think the "Giro first as an Italian" theory has some merit. Gilberto Simoni was at his absolute prime in 2003, and said he'd push Lance in the Tour that year. But he tried a Giro/Tour double and later said that was a big mistake as there was no way he could double peak like that, and finished like 20th in the Tour and was never a threat (he did win a mountain stage though). But this "Giro first" can't only be the case, Cunego focused on the Tour in 2008 and skipped the Giro entirely, and he didn't ride that well.
A lot of Italians simply don't seem that interested in the Tour. I don't know that he could win it, but Danilo DiLuci might have been able to podium in the Tour had he focused a season on it. But I don't know if he's ever seriously ridden the thing. Same with the now retired Salvodelli.
There's talk in Spain of moving the Vuelta back to late April (and nudging the Giro back a week) like the old days. The concept is that riders might race the race more to win, and not as a leftover from the Tour, or prep for the Worlds. Spain sure is prettier this time of year, more than the dry, brown of late summer. But would that keep Spanish riders from focusing on the Tour?