I mean in 2020 Wilson still threw 40 TDs, over 4000 yards and won 12 games. You're not benching that guy even if you have the next Patrick Mahomes on the bench sorry.
2021 Wilson "faltered" (he still finished 5th in QB rating, throwing 25 TDs to 6 Ints for the season despite his injury) and yet we got rid of him the very next season in favour of Geno, who played better than him in relief. So yes, that's exactly what happened. Of course if you bench Wilson at that moment for Geno you don't have have the leverage to get a kings ransom in picks from the Broncos, so the FO and Carroll played it perfectly.
Peyton Manning also went 0-3 in his first 3 postseason games. Didn't win one until his SIXTH year as a starter.
And finally, the Baker Mayfield comparison - you know there's a possibility that Mayfield is actually also a good QB. After breaking the rookie TD record for a team that finished 0-16 the season before, he subsequently led the Browns to their first winning record in 14 years, best record in over 25 years, broke their league record playoff drought and won their first playoff game since 94. He also had a pretty good season last year and won a road playoff game as a wildcard. Just because he was stuck at the Browns doesn't mean he can't also win a superbowl down the line - Matt Stafford didn't win a single playoff game in 12 years at the Lions then won 4 and a superbowl his first year as a Ram.