The situation at Manchester United is slowly getting out of control; it wasn't like this for them, and the club's culture makes it uncomfortable for them to even perform well. They have been struggling for a long time, and even with the addition of players, nothing has changed, which isn't helping at all. However, it appears that they are dealing with an internal issue because they have been too stagnant for a long time. And they have not been able to fix what the major problem is so they still have a long way to go, because I don't think they have a solution yet them self because they keep failing so they need a new coach or even players.
Honestly Manchester United has struggled for the longest and I agree with you that ordinarily the culture of the club do not allow them be in such a position this long as the pressure from the team alone keeps everyone on their feet and this includes the coach and the player but it keeps looking like they now settle for the compromise and nothing is happening, there is hardly a noticeable progressive improvement, only loads of promises and unending hopes and expectations that almost never comes to fruition, a new coach all players may not be the solution but a system that keeps the current coach and players on their feet to birth results.
Sincerely speaking the Manchester United case has been a dicey one, one thing Manchester United have been missing out is the fact that nobody has been able to replace Sir Alex Ferguson and this is because no coach has been able to stay for how long Ferguson stayed, the fans want to see instant result, the management of the club still want to see instant result and this has lead to management replacing upon replacing of coaches and players, and so far nobody has been able to still build a solid team that will give them what Ferguson gave them.