Like I said, if Mourinho didn't have this kind of personality, he would probably never have been as successful in the first place. When it's bad it can get really bad, but when things work then there are not many better than him. Yes he did buy the players but he obviously didn't know how they were going to get along and how they were gonna respond to him.
It does have to be noted that Mourinho's success has been massively different in the second half of his career than it was in the first half. In the first 8 or so years (Porto, Chelsea, Inter and the first year or two at Real) he had incredible success. He was undisputedly one of the best and most successful managers in the world, up there with Fergie and Guardiola who arrived towards the end of that period. He looked a real possibility of going on to be up there with the greatest of all time.
However, in the following 7 or 8 years (the last year at Real, Chelsea and here at Utd) it's been completely different. He did get one premier league win, but even that was during a period where the league was at it's lowest quality since the premier league began. He also did win the Europa League with us, but considering we were comfortably the best team in the competition it would have been quite a failure not to. Otherwise he's ended up with massive issues with all three clubs, having far less success on the field than he did in the earlier part of his career, and falling out with most of the players (especially the best players) at every club. At Chelsea and Man Utd at least, he has also proven incapable of dropping players who are massively under-performing, and just in general he seems to be struggling somewhat to adjust to how an increasing amount of teams are playing.
I was one of the ones who wanted Mourinho here. I gave him the benefit of the doubt that the issues he had at Real Madrid and Chelsea were due to them being clubs where player power was just too strong. Then I saw the fact that we improved in his first season, then further improved in his second season, as a sign that he would get there even though I did have a number of issues with what he was doing. Even at the beginning of this season when he was blatantly trying to make a point by playing midfielders in the defence at the expense of results, I wasn't happy but I was hoping he'd get his head screwed on right and get on with it. However, he hasn't. He's continued making ridiculous decisions on the field, making ridiculous comments about our players to the media (some directly, some 'leaks' which are obviously from him or his team), completely unable to get us playing as a team, completely unable to get the best out of any of our players, and just in general being a failure and creating a toxic atmosphere at the club.
I do have questions about Pogba's mentality, but the emphasis there needs to be the word 'questions'. We don't know whether this is the true Pogba and whether he'd have these issues forever and under any managers. Or whether the issues with Pogba are only happening because of mismanagement above him. The fact that he hasn't had these issues under any other manager including some others who can be quite strict, and that he has been our best player even with the issues with this manager, indicate to me there is a significant chance that he will come good if we get our shit together on and off the field. It's not a guarantee. But the odds are significantly in his favour.