The problem isn’t the back-up quarterback. Bridgewater and Brissett are two of the best back-ups in the league. Tua is just really good, much as some people can’t accept that, and no backup is going to give us what he gives us.
Winning with a backup quarterback is about your running game and defense, not your backup quarterback. Cooper Rush went 4-1 for the Cowboys this season. He threw for 5 TDs in those 5 games and never cracked 240 yards passing. In one of the wins, he threw for 102 yards. Cooper Rush stinks. The rest of the team was just good enough to win with a mediocre, backup quarterback.