Manchester United have hired and fired quite a lot of managers ever since Fergie retired, and looking at United's performances this season, it is easy to predict that Erik Ten Hag is going to go in the same way, he'd be fired sooner or later. Having said that, even if he is fired, that would not solve Manchester United's problems, they would still be struggling because the club has already lost its winning mentality and these days other clubs are no longer scared to play United, because they know that they can beat them. I don't know what Manchester United needs to do to get back to glory days, but i am pretty sure it would not happen anytime soon.
The only time Manchester United fans would seize being heart broken concerning their teams progress is when the Glaziers family stops being in control of the major affairs of the club, they're running the club poorly and investing less into it, which is affecting their performance on the pitch, another problem is that most of the executives at the board level are incompetent of handling their jobs properly and the Glaziers don't care so far they're receiving a fat dividend annually.
The problem is not about Erik Ten Hag, if they Glaziers doesn't handle the club properly then the problems in the club would never get solved no matter the coach they bring in, the club needs restructuring and several incompetent people from the players down to the board needs to be changed as well investing properly into the training section and other sections that needs new development.