Erik Ten Hag should have deserved to be fired, especially since Manchester United's performance this season has been very disappointing. Even this season, finishing in 8th place and only collecting 60 points was the worst record since the David Moyes era.
I know Ten Hag performance wasn’t really good last season, and I never expected Manchester United to end the season at the position which they ended it, but from the way Manchester United played last season, I won’t be blaming only the coach for their poor performance, the players always have to be blamed, they have to change their mentality also, some players played like they are not really ready to play for the team, or they are not paid for what they are doing. If Ten hag is being sacked, there might not really be much difference with the new coach that will be coming if the players don’t change their mentality.
Initially I blamed Erik Ten Hag for Manchester United's bad results, but after finding out that they still had good luck with this Dutch coach, maybe continuing to work with him wasn't so bad. If everything had to start from scratch it would only make things difficult for Manchester United and it wouldn't necessarily be possible for them to get the same results as winning the FA Cup.
On the other hand, the transition process will take quite a long time and I think this is just the final finishing touch that Erik Ten Hag has to do with his players so that management's decision to fire him doesn't end up being detrimental later.