With the exception of Stafford, has there been an example of an established vet changing teams recently that actually paid off? Rodgers? Wilson? Ryan? Wentz? Watson?
Maybe not "super recently", but IMO there are tons of examples of established vets moving to new teams and finding significant success. Off the top of my head:
Warner to Cards
Brees to Saints
Cousins to Vikings
Smith to Chiefs
Manning to Denver
and as Old School mentioned, Carr, Jimmy G, and Baker Mayfield all found success with new teams.
Older examples include Montana, Cunningham, and Vick all found success with new teams late in their careers.
McVay is a hell of a recruiter, and it's easier for players to change teams now than it used to be. I can see a scenario where a talented vet, stuck on a perpetually shitty team, would be sorely tempted to answer McVay's pitch to join the Rams.
EDIT: Fuckface McCheat to the Bucs is another one