They probably will if the opportunity comes along, and there's literally no way Brady is dumb enough to take it. He's not going to go to the team that ended Luck's career (and damn near ended Manning's before him), to play for an owner who said Luck's shoulder injury was in his head right before he missed a full season due to it. And to play for a team and fanbase that hates him and has contributed more than anyone else to underhandedly smearing him and trying to taint his legacy.
I'm not saying this in a "Brady will never leave the Pats" sense, because I'm solidly in the never-say-never camp on that one. I think, hope, and pray Brady will retire a Patriot, but until the day he hangs him up I'm not going to pretend to be certain or even confident of that. But if he does leave, it won't be for the Colts of all teams.