I think his shitty way of treating players explains it. They've had enough of him.
Shaw has been excellent this game. He's clearly still always had it in him. I'm sure a manager who hadn't acted a total cunt towards him would have got that out of him about a season ago. Martial looked a potential world beater two seasons ago. Now he's basically frozen out with Mourinho actively trying to bin him off in the summer. It's a mess.
I honestly believe that at this point we have an excellent squad and with a manager who got the best out of them we'd do great.