It seems there is something that made the board think twice about deciding to fire Ten Hag, and maybe if they take that decision, it is feared that Man United will be even worse. Man United has already spent too much money on Ten Hag, and also so many of the players he brought to Old Trafford. So if there is a new coach who replaces Ten Hag, it is not certain that the person will be suitable with Ten Hag's legacy, especially since the season is already underway. If the new coach even wants his own team, then the board will have to dig deeper into their pockets.
The new coach is not obliged to work with the players that ten Hag brought to the team, look at how many changes have taken place at Chelsea in recent seasons, and this was provoked by changes in coaches. So of course, this will be a painful move with a change of coach and a possible change of many players, but if this is necessary to improve the team's results, then it is probably worth doing. It seems that ten Hag is a good person, and dismissal is always a difficult decision, but in this case, he only asks to give him more time, and there are no changes for the better.