You don't have to believe... You don't believe don't mean it won't happen sooner or later. The players are keen to improve and win the Premier League Competition that's what that matters, they have one of the strongest fanbase during home and away games. Also they have a top, sound and great manager who understands the game of football and is constantly moving and evolving same way football is evolving.
You still haven't learnt that, the evaluation of Erik Ten Hag had to do with two seasons and not just the one from last season. If it was that alone, Erik Ten Hag would've been sacked, bit he had a great first season and the second came with lots of setbacks.
The beautiful thing is that setbacks are cool and they're part of the journey. The bad days and pains are also there so Manchester United fans would appreciate the good days. They will get better and Erik Ten Hag will win the Premier League Competition next two seasons. With significant signatures, they don't need 3 transfer windows, even youngsters can have a rapid impact innit the squad.
I know that first season definitely did helped him stay, but I think the real reason is that Jim Ratcliffe basically wants to keep him until the team is better. The idea is that, they are not going to spend bunch of money on useless players again, that was Glazers method, to just get the fans hyped, their new system will be just getting future potential superstars, like how Chelsea did with Cole Palmer, and United have a few, like how Mainoo was promoted to main squad.
So all in all, why change manager all the time, when you are not entirely sure about the roster itself, if you agree that roster needs help, then how could a manager get good results with a roster you are not happy with? That is why first they will fix the roster, build a good squad, and then they will see how ETH is doing. Unless he starts to do exceptionally bad of course, like be 15th or something, then yeah he would be fired.