If Brady fails to win another ring in his career would it prove that he is overrated?

You forgot to mention Cel suited up to play in the first game of the 2008 regular season and as a starter ended up going 10-5. That's Belichick's team more than it is Brady's. I can't say he's overrated because he still put Vinateri in a position to give New England the win twice in the Super Bowl and generally he's very accurate. But he also had the luxury of playing Indianapolis a handful of times in the playoffs under winter conditions. Ty Law was their Darrelle Revis, since he left the secondary has been mediocre at best.