If you have a chance to get a potential Franchise QB you make that move everytime.
Why would you do that if you already have a franchise QB, aka GOAT, set for the next 4 years?
You make that move in an Andrew Luck case. Not for Bridgewater, Johny Booziel ,etc..
And even in the Colts/Luck choice, there were several question marks over Manning back then, had he been completely healthy, coming off a IR season for a injury like a broken foot or something like that, they would stick with Manning and trade luck for a universe of picks.
Well we can't predict Irsay's call on this, based on what he said a few months ago they could make the move even without Manning's arm and neck concerns.
But that's a totally different case. I see no reason to believe Brady will decline to a level where he can't perform anymore during his current contract. As far as I know he doesn't drink, is always in good shape, hard working, he should have a balanced and healthy wise diet because Giselle needs it as a supermodel and he may or may not follow but of course there is a lot of nutritional evaluation on their house. They have nothing to worry, that reflects on the field. And the most important thing, Brady is probably one of the smartest QB's ever, if he feels his arm is not what used to be he will adapt his game instead of being stubborn. Brady at 50% is still better than all this QB class.