In principle I agree, but it still just doesn't compute for me. There are too many things that don't make sense in these answers.
Poor recruitment: Has it really been that bad, if we look at the signings at the time they were made? The lack of solid CMs is undeniable, granted, but I'm not sure which options we've failed to take. For the other positions, our signings haven't been worse on paper, at the time, than so many other big clubs. The players just seem to forget how to play football once they arrive. We've had a remarkable number of promising youth players come up through the ranks, but once they get settled into the squad, they invariably fail to remain exciting. We've signed loads of expensive players for whom we had to compete with other big clubs, and the same thing happens: they turn to shit either immediately or after a promising first season.
Substandard coaching: Indeed, but what's the explanation for the fact that the players often do just fine when they're playing for their national teams? It's not as if they spend enough time on international breaks to where their NT coaches can completely transform them, only for them to instantaneously revert to shit once they return to the club. I'm inclined to agree that we don't appear to have great coaches, but at the same time, I have to feel that it can't just be that. Players spend 90% of their time training with the club's coaching staff, and if these were so incompetent that it literally ruins the players, they wouldn't magically do fine the moment they go play for their national teams or their next club after leaving. But routinely they do.
Club culture: We're on our fifth manager in nine years, so I'm not sure how much more often we could realistically have changed them. Keeping underperforming players has certainly been a problem, but at the end of the day, practically every player at this club ends up underperforming. Almost none of the signings work out. Something like 75% of our players for the last decade can be categorized as an "underperforming player who should be moved on," and that's not something any club could do. I don't think the issue is so much with keeping players who aren't performing, it's with whatever it is that causes practically every player to underperform at United.
Lack of identity: How many clubs can genuinely be said to have a meaningful overall identity, if we're being honest? Almost every team plays the way their current manager tells them to play. I think people overrate this notion of identity as a permanent thing. What identity has Real Madrid got? Can't Liverpool be said to play to the whims of their latest manager? What's City's identity besides buying an endless cavalcade of stars and having a competent manager? This idea of "football DNA" is a bunch of mumbo-jumbo. Every club just does whatever it thinks gives the highest chance of success. It's just that this hasn't worked at United for a long time. With a revolving door of managers and staff for the better part of a decade, are we to believe that absolutely none of them had an ounce of "identity" in them? What are the odds of that? If anything, Ralf was supposed to be Mr. Identity. It's literally all he's known for.