"The only reason he has the chance of winning is because he has an incredible car," French Canadian Villeneuve, who has been signed up by F1's new French broadcaster Canal+ for 2013, said.
"His only problem is that he does not learn from his mistakes," the former Williams and Sauber driver is quoted by France's RMC Sport.
"I found all of last year's nonsense amazing," continued Villeneuve. "He didn't change from the first to the last race.
"It's a shame because he is a very fast driver."
Of the other F1 drivers, outspoken Villeneuve admitted that his favourite is Fernando Alonso.
"The best car is certainly Adrian Newey's Red Bull. But apart from Alonso, there is no driver capable of driving at the limit of the car the whole race.
"When Vettel does, he makes mistakes," said the 41-year-old.
"The only standout is Alonso.
"After him, maybe Lewis Hamilton. He is no longer at McLaren, with his family, and so he is not protected any more, but he is a fighter so it will be very interesting," added Villeneuve.