It's not super complicated
ManU had
David Moyes, Louis van Gaal, José Mourinho, Ole Gunnar Solskjær, Ralf Ragnik and Erik ten Hag and now almoran under preforming all of those so far. There have also been a few interim managers, such as Ryan Giggs and Michael Carrick
Wenger late stage, emery got eaten alive by this team. And Freddie as and intern manager.
If cultural issues are easy to solve why is arteta the first one off all these to do it? Not sure why you'd deflect from the question unless you've an agenda or something.