Now we will find out just how important Russell was to winning SB48 and losing SB49. We needed Russell's 4th-and-7 TD pass vs the 49ers in the NFCCG just to get to SB48. We needed lots of key plays from Russell in the narrow regular season wins vs Houston and Tampa Bay in order to get HFA through the playoffs. (and we needed Shoeless Dick Sherman's pick-6) For SB48 it's fair to say that Carroll and Bevell's system put Russell in position to be successful, and Russell did his part.
For SB49 I'd say that Bevell put Russell in a terrible position with a playcall that relied on the weakest part of Russell's game and targeted the worst receiver on the team, instead of using Russell's strengths (e.g. mobility). Russell created that outcome by "trusting the playcall" instead of knowing enough to see, pre-snap, the play design wouldn't work since it relied on Jerome Kearse manhandling Brandon Browner, and either targeting a different receiver or changing the play.
So, ultimately, we don't have to have the greatest QB of all time, we just have to have a QB with some strengths and an OC and coach who have a plan to consistently put that QB in position to use those strengths. Pete's preferred way is defense and running game/balanced offense and winning the turnover battle. That 2019 Tennessee Titans team won playoff games with Pete Carroll-style football.
https://en.wikipedia.org/wiki/2019_Tennessee_Titans_season#Postseason A QB like a Ryan Tannehill can get teams to a Super Bowl (and win) with a good enough defense, running game, and winning the turnover battle. Unless, of course, you're unlucky enough to face a loaded KC team with a Patrick Mahomes on his rookie contract in the conference championship.
FWIW, Tom Brady's last pass as a Patriot was a pick-6 thrown to that Titans defense in the Patriots wildcard-round loss to the 2019 Titans.
Our young D showed some very nice flashes in preseason. Our OL and running game as well. We appear to have very good young tackles now. A game manager QB who has a few nice strengths could be all it takes for this team to become a playoff contender again.