The OP may think he knows what he's talking about and others may think so too but he clearly does not. Sitting QBs does not make them better. As in all things, only experience makes them better.
Rodgers was a natural and taken by the Packers before they were looking for a QB just because other foolish teams like the Bears let him drop. Sitting for a few years had nothing to do with what he became. He was better than Favre from the get go but football politics say you don't oust a legend like that so the Pack had to wait til Favre was kinda ready to step down.
Brady is a system QB. No team in the league projected him to be a day 1 starter. Patriots held on to more QBs than usual to see what they had in the their promising 6th round pick. In a system predicated on players working hard to move up, Brady did that hard work and showed himself worthy. Bledsoe went down and would lose his job, for the first time but not the last, to the QB who was just a better fit for that system. While the casual fan may think the Pats have been all about Brady, that's never been true. They've always put a very good defense on that field and afforded him good protection and talent around him as well. The Patriots were just right for Brady and Brady was just right for them. Both needed each other to bring out their best.
Peyton started from day 1 and always said it was the best thing for a QB, a fast track to learning the game better. Say what you want about Peyton and the post season but I don't believe any other QB carried his team on his back for longer than he did.
As far as the promising QBs the OP mentions in order to then disrespect and act like they have no business being thought of on the same level of the aforementioned 3 greats, let's look at the reality of it. He mentions the future greats as Cam Newton, Matt Ryan, Andrew Luck, Russell Wilson, Jameis Winston, Marcus Mariota and Derek Carr. Let's go ahead and take out Winston and Mariota cause I don't think they were ever thought of as going on to be "greats" but rather just good or even very good. And going to shit teams will never help their cause. Now let's take out the former ROY and the 2015 MVP. Why? Cause that 2015 season was a fluke and he's a very selfish player meaning he simply doesn't have the right mentality to be great over an extended time period. He's too up and too down and too self absorbed. Leaves us with Wilson, Luck, Ryan and Carr.
Ahh, Andrew Luck, the next Peyton Manning. Injuries early on and a shit franchise that became all too much about putting the entire team on the QB's back have made him look like anything but the next greatest. Maybe things change in the future but this case points to 2 things a career great absolutely requires, long term good health and a solid team around you. Andrew has had neither and so it goes.
Matt Ryan is intriguing. A very good QB who has worked to get better and seems to each year. Again, look at the team he's on. A QB like Brady has played with nothing but good defenses while the guy Ryan has played with nothing but bad ones. If you don't think it's harder to win when you consistently have to score more than 30 points to do so, you're very ignorant.
Russell Wilson made his team a better one since the first day he took the field for them. It couldn't have been more evident so the fact the OP and other casual fans continue to diminish his importance and give all credit to the defense just goes to show how little these fans know. You can't win with no offense and without Wilson, Seattle would have no offense. Has a QB ever done more while being afforded less protection and viable weapons? I think not.
Derek Carr seemed to be taking that next step with the crazy Raiders, before he went down with injury. Certainly he has done more on that team than the parade of QBs who made the attempt before him. It will take a special QB to turn that franchise around. He may very well be just that.