I agree with you, they need a total overhauling of players and of the Man united management team as well, they can't be doing the same thing over and over again and be expecting a different in result. In fact it's better they even start from the scratch and offset almost all the their players and retain a little key players if they can get the needed results, and further restructure a whole lot of other things going wrong within team's management board, this way, they will be able to figure out what is really the problem with the team and if it's not gonna help them solving their almost a decade of problem.
They don’t need to change the whole team before they begin to see results, they just need to offload the players that are not needed right now in the team and try to make the best out of their current poor state. I have seen Arsenal passed through this stage some years back and they were able to come out of it. I also saw Chelsea passing through this state and they are also getting out of it gradually. It is just a state to strategize again and be the best that you can be for the future competition. Manchester United is a big team and they have the resources to make this happen.
This past season was very bad for them, they were not far from the relegation zone which is very terrible for a team like Manchester United and if care is not taken they may end up being relegated so they need to act fast. It really a slap on them. They should strengthen their defense and sign a top striker to begin with only then can they compete properly as hold days with the help of the coach.
It is really baffling that they have a new coach but they can’t still finish in a good position last season. You can’t focus on leagues outside and forget your domestic league which gave you the qualification to be playing in that league in the first place. They almost got relegated for the first time I’ll witness since I started watching football. They should be more careful and prioritize more what is more beneficial to them and doesn’t call for any doubts for what they just did last season.