Maybe it time for Manchester to do something. I mean they are great club Arsenal is also but last few season Manchester have problem with picking goad coach. It was look promising with Solskaer in start but seem like he is loosing the edge.
The problem with United is not only the coach. Their players also need to do better. Even if they're still under Sir Alex they won't be able to perform at their best if the players don't give their all. Take a look at how they interact with the manager, like Poga to Jose. It needs to be fixed, sometimes having a 'mediocre' player is better than having 11 players with a huge ego that don't want to play according to the managers tactical approach.
You are right but Solskjaer also take a part why Man United sucks so bad this season. I still can't believe he sold Sanchez and Lukaku, look at Rashford, he can't make a goal on arsenal match. Even if Man United change to another coach, it will not guarrentee Man United back to winning track.