Look around the league. The odds that our next QB is not a **** show are pretty low statistically speaking. All the QBs you listed could have a title contender built around them and are likely much better than whomever we replace Brady with.
And yet Eli is the only one who ever actually won anything, and those teams weren't built around him by any stretch of the imagination, so that's true only if you define title contender in extremely nebulous terms that don't actually mean anything. I'll take 2-3 years of being the odds-on, guaranteed-to-make-the-AFCCG favorite over 8 years of being a four seed that nobody expects to win anything, without a second thought. For every 2011 Giants / 2012 Ravens that catch fire for a month, there's 30 teams that predictably go on the road and get their **** kicked in by truly elite teams benefiting from the play of all-time great players like Tom Brady. We've been on the right side of this matchup for so long that I'm having trouble grasping how so many people here still fail to understand it.
As for the current state of QBs, I firmly believe that's equal parts shortage of talent and lack of development. The Pats develop QBs extremely well: two weeks from now, Brady, Garoppolo, Brissett, Hoyer, Mallett and Cassell will have started games in the NFL this year. Garoppolo and Brissett both look like real starting NFL quarterbacks. I'm as confident in the Pats as I am in anyone else to develop the next young QB who breaks through, and there is talent to be found in the NFL draft. Prescott went in the 4th, Carr went in the 2nd, Wilson went in the 3rd. You just have to have the talent evaluation and coaching to draft and develop the right QB in the right way, and you have to have a coaching staff that can scheme to your young QB's strengths.
Most of all, though, I think posts like yours are continually understating how good Brady really is,
and how consistent he is. If Brady was 'just' a top 5 quarterback, then sure, move on from him a year or two early like Belichick does with every other high-priced veteran. But a) Brady isn't highly paid, he has like the 20th highest cap hit this year, and b) but Brady and Rodgers tower over every other QB in the league. Having one of them is by far the biggest advantage in the sport, and the only explanation I can come up with for people being in some weird hurry to end this era is that I guess people just really don't understand how irreplaceable it is. Last year's MVP is currently putting up middle-of-the-road production, and this year's MVP frontrunner was so unimpressive last year that his team traded up in the first round to draft his replacement. The guys I quoted earlier -- Ryan, Eli, etc. -- are close to the best case scenario for Garoppolo. It's even more likely that he ends up being, say, Alex Smith: the kind of QB who's just good enough that you're reluctant to replace him, since you can build an actual playoff team if you perfectly build an offense around him.
We have the rarest and most valuable commodity in NFL history, who is showing no signs of slowing down, and some of you guys are so loaded up on unverified potential that you're downright eager to throw it away for a guy who's going to command $20M per year on 2 NFL starts.