You are using examples of teams with a strong veteran presence.
You are also bringing up teams with Super Bowl rosters
We heard about the team only meeting after the 2018 Steelers loss. It all changed after that.
Players make mistakes because of poor concentration and falling back to earth because they are inferior to their opponent.
When teams don't have the talent to overcome them the mistakes and penalties become magnified.
You'll notice the # of penalties committed by the team this year was in-line with past of BB coached teams with the exception of 2020 and 2013. 2014 had 120 penalties by far the most of any BB coached team in the 2000s...but since they were loaded with talent and battle-tested they overcame them.
I agree some execution -related mistakes should have been corrected but that is not why they lost to better teams all year and got throttled last night.
Good talent. Rookie QB who did well but lost consistently to more talented teams.
That was the 2021 Patriots