The NFL thread is an interesting place for this take, as the NFL is a league where all the time we see teams come out of seemingly no where to make the playoffs and even win championships.
Philadelphia won a super bowl. They have since replaced their coach and QB. Were their executives a failure? Atlanta was basically 1 play from winning a Super Bowl, since then they've fired their coach and struggled. Are their execs failures? Denver lost a super bowl with an elite offense then won the next one with an elite defense, but they've fallen apart since then, did Elway get stupider? Can they be regular failures and still put together teams that good?
I went back through the last 13 super bowls (26 teams) and found that it looks like 17 different teams have made an appearance in that time frame. Aside from New England/Brady being a cheat code/actually smarter and better than everyone else, it instead seems to me that there are a pool of about 2/3 of the teams in the NFL that are ok, that could genuinely compete in a normal year, sometimes those teams take a step back to rebuild or find a new QB, but then they're back a few years later and eventually have a big enough season to make a Super Bowl.
Then, there's about 1/3 of the league that is regularly bad - Jacksonville, Detroit, Cleveland, Chicago, Las Vegas, the Jets, the Washingtonians, I'm sure you could add a few others. Those teams make the playoffs like once every 5 or 6 years, and are constantly changing coaches, failing on high draft picks, etc. For those teams, it genuinely starts with ownership - culture issues like DC or Jacksonville, consistently bad hires like Cleveland and Detroit.