If the players try, and fail, and are clearly the better team, that's on the manager.
If the players don't try, and fail, blame should fall squarely on the players, and the manager should be questioned regarding the possibility he has lost the team.
At the same time, if the players have too much power, and decide to quit on anyone who doesn't fluff them before every game, then you also have a problem, an even bigger problem, and I think it's pretty clear this HAS been the problem with United since Fergie left.
Mourinho needs to go Conan the 'fecking' Barbarian on these guys, and start chopping the roster. So, has Mourinho lost the team? Maybe. Is the team behaving like a bunch of precious primadonnas? Yes. I'm going to side with Mourinho, he has taken us from not even qualifying for the CL, to 2nd place and a Europa League trophy with the shower of shit he inherited from LVG and Moyes.