I think Madrid is a unique case tbh. You need to win things asap because the fans and boards are not happy if you fail, whatever the reason is. I think that's why Ancelotti is loved. I think other big clubs have some leeway (1-2 seasons) for a new manager to fix things and rebuild the squad unless they're doing extremely stupid things like playing GK upfront or something similar. Well, hopefully things change with Alonso (although that seems unlikely).