Handing over the club to a new manager means placing more trust in the new manager than the previous manager and expecting the team to perform well under the new manager. Manchester United expected that and relied on Ten Hag but far from improving the team's performance this manager has consistently deteriorated under him.
In the case of other clubs, if a new manager is appointed, if that manager does not perform well, then the manager is removed from the responsibility of the next season, but Manchester United did not do that, they only trusted this manager. Under this manager the team performed poorly for the entire season but they trusted this manager for one more season which resulted in this manager consistently making the team a bad team.
Since Manchester United has extended the contract with this manager for one more season, this manager may be seen in Manchester United for one more season, but the manager of Manchester United may change in the next season.
It's very obvious that Erik Ten Hag is having a slow start this season, I think the board are already aware of that but you don't expect them to just sack him immediately since the league just started and they just extended his contract, they'll wait patiently to see how it goes and if things doesn't get better by the end of the year then they'll have no option than to terminate his contract by January, and I feel that there's a replacement already in the team for him in person of his assistant (Ruud Van Nistelrooy) who was a former player of the club and club legend. Talking about other clubs, remember that Arsenal didn't sack Arteta even after two years of poor performance they gave him time and watched him become successful, however Ten Hag was successful in his 1st season, he finished in top 4 and won a trophy and even participated in several finals and even though the 2nd season in the EPL wasn't as expected cause he finished in 8th position, atleast he still Won the FA Cup so that's enough reason for the board to consider giving him another chance and if he fails to deliver they'll definitely sack him, afterall they were in talks with other potential managers during the Pre-Season before they considered giving Erik Ten Hag a second chance.
Lol
it is very unfortunate when a club as big as Manchester United has to obey a manager like Erik Ten Hag, let alone trusting his slow process, even though with almost 3 seasons, Erik Ten Hag should have been able to provide better improvements but as far as I can see Man United's performance is still the same and tends to decrease, the amount of money to recruit players also does not help the club at all. If the club is willing to accept all the risks, they must also be prepared if they end up finishing in the middle of the table on par with average clubs, even now Man United does not look like a top club because its quality is decreasing.
I don't understand what you mean by Manchester United has to obey Ten Hag, my question is, is Erik Ten Hag bigger than the club or is the club bigger than him? The club didn't even obey a high profiled manager like Mourinho talk more of Ten Hag, what you don't understand is that the board had a meeting at the end of last season to deliberate on sacking him but pardoned him based on his achievements in just 2 years of arrival which is participating in several finals about 6 or so, winning the Carabao Cup and Winning the FA against the most outstanding team in the league, it's now left for Ten Hag to make use of his second chance wisely cause if by January the board are not satisfied with the teams performance then he might end up losing his position as the manager of that club.