Mourinho doesn't like players who, not are unwilling to defend, but who won't put defence above attack. He also rarely rotates, he's a guy who has made a career on those Newcastle getting 5th or Leicester winning the league seasons. By naming an almost unchanged 11 throughout the year you'll have a better performance squad... but one that burns out, which is why Mourinho's teams perform better for a while then go to crap. Not only is his first team burned out but all the replacements will have barely played for two years.
I suspect for instance that Lingard is playing so much as he can run him into the ground and is seemingly always available. It's likely why he binned off Bastian without a second thought, figured he'd be constantly injured so why waste the time. Why he's backing away from using Shaw for Blind. Martial and Micky got injuries coupled with not being the kinds of offensive players he likes. He wants a reliable non injury prone team of people who will kill themselves defending when he asks it.
How can the supposed greatest or one of the greatest managers fail completely to create a legacy at a single club, no success beyond 3 years and performances dropping off after 1.5-2 years max.