Jimmy helped his trade value today, let's just say that.
People who want him to replace Brady, though... I dunno what to say to that. We'd have to replace Brady in the next year (not going to happen) or pay a cap-crippling amount at QB by franchising Jimmy.
And more importantly, it undersells how good Brady continues to be, for starters, and it undersells how good Belichick/McDaniels have been at getting these guys ready to play. 2 years from now, chances are good that Brissett will be as good as Garoppolo was today, and then we can have this whole discussion again.