That his claim has gone unchallenged surprised me too. When Brett said this, everyone thought he was nuts. Though McGinn did call this year.
No one knew who Ryan Grant was when Favre made his "most talented team" comment. In fact, while I am not sure of the dates, Grant was such a late preseason addition, Brett was likely complimenting Brandon Jackson as his starting RB. And this team had Junius Coston, Tony Moll and Aaron Rouse get starts.