Those contracts are one of the huge reasons NE was able to win all those Super Bowls. If Brady was paid what he was worth, they would have had way less payroll flexibility and would have lost out on a lot of good players.
Not picking on you, but using your post as a springboard, but "what he was worth" to whom?
Maybe I'm not looking at this the right way, but highest bidder at auction (i.e. free agency) isn't the only measure of what someone is worth, nor is cash the only way to measure compensation. Does anyone honestly think that if he signed on in 2001 with Detroit, or the Cardinals, or Dallas (I think they were last in the NFC East in 2001) that we're still talking about him today as the "GOAT"? I'm not saying he's Ryan Leaf, or that he didn't earn what we're talking about, but it's a multi-variable equation. The magic with Brady is that he was able to incorporate that thinking for 20 years, not three or four, as many other star players have.
When I worked at GE, I was in Atlanta and in Connecticut. You could make good money taking a gig in Erie, PA, or in any of 25 cities across the US - Morrison, IL or Hickory, NC or Dothan, AL, or Salem, VA - places you had to drive to or take smaller prop commuter planes. Even Plainville, CT was a decent place to get a decent salary. The dream job? NBC, in New! York! City! You got to work in Rockefeller Center! Hob nob with Conan O'Brien! Cut through Studio 8A on your way to wherever! See Tina Fey, Darrell Hammond and Seth Meyers in the elevator! And... take a 25% pay cut, even accounting for city living. Because any NBC job that opened up was flooded with applicants all over the company, and that's even assuming they weren't going to go to a seasoned candidate from a competitor (because of the industry). I think that's partly the case here. You get a legit shot at a champeenship EVERY SINGLE YEAR.
Brady is the best, no doubt, but he could walk into camp each season, and no matter how many question marks there were across the roster, he had a decent shot of getting deep in the playoffs, and at that point EVERY Super Bowl is in reach ("Any Given Sunday"). Can any other QB over that span say that?