It is just really difficult for Manchester United to achieve this comeback with Erik ten Hag as it seems. Because there is still no sign of any recovery. They just continue to lose points which caused the gap with top four to go up to nine points. There are three teams between as well so it is very hard for Manchester United to make it to the Champions League again.
I think this must be an enough reason for the board to sack him by the end of the season at worst. If they were a title contender in the previous season then maybe Erik ten Hag would have still had a chance to stay longer even if he completes this season poorer.
Do you mean comeback to the top 5 in EPL standings? You're right, it seems very difficult to return to the top 5 because Man United performs very unstable and the point gap with Tottenham in 5th is quite large. If there is no change with Man United, I think Man United probably finishes in the 6th place for this season. However, it won't be easy, West Ham and Brighton are competing for the same position. Man United also must be aware that West Ham and Brighton aren't weak teams.
Yes, it is time to fire Ten Hag. After this season is over, I am sure Man United probably fires Teh Hag. He failed to improve Man United, he also made some problems with players. It is not a wise decision to keep Ten Hag in the club if he often makes problems.
I mean a comeback to top four because it is the only way of joining the Champions League through the Premier League again. If they finish as the fifth or below then this is a big downgrade in performance which is really likely to happen if Erik ten Hag can't find a way to make this team start recovering.
But at this point I don't think he can do so. Manchester United's inconsistencies continue to cost them too much and I think the last situation of top four will be like four of the current top five teams will have finished there. It is too difficult for the Red Devils to climb there after this big gap.