Nobody is a saint. The problem is Messi is a nasty player to deal with. A little dictator is an accurate description. He can't be managed at this stage.
You think Koeman wouldn't want to rest Messi? He can't do it because then Messi will get pissed and shit's gonna hit the fan. You really think he beleives Messi gets more tired if he doesn't play
lol
, that bullshit was to save faces that he's not really the top dog in the team: Messi is.
The fact that Martino and Setien weren't top managers doesn't change the fact that these players are going the Galactico route. Nasty manipulative characters who basically run the team and turn every manager into a submissive puppet. Unless they become like Valverde, a soft nice dude that lets them do what they want. The Galactico Madrid's main players like Ronaldo, Roberto Carlos also did what they wanted. Also in that period no manager was good enough and they started to sack them after months. Also, big surprise, they started to get stuffed in CL like we have been.