Manchester United were stupid to buy Maguire and gave him very high salary but the player is smart to recognize that he will receive same high salary if he leaves Manchester United and joins any club in Europe. With his poor performance for Manchester United, big and rich clubs in Europe will no longer want to have interest to buy Maguire.
His only chance to receive similar or better salary is from Saudi Arabia but so far, no offer, no rumor about interest from Saudi Arabian clubs. If such opportunities won't come, Harry Maguire will stay with United, complete his contract and fill his pocket.
Harry Maguire almost moved to West Ham, but suddenly the process was canceled and several media said that the salary negotiations did not reach an agreement with the player because he asked for a salary that was almost the same as Man United's. Harry Maguire was one of the players who failed to shine at Man United even though when he played at Leicester City his performance was quite convincing and in his second season with Man United his performance was far from expectations. Man United also never stopped Harry Maguire from leaving, but the English player was not willing to leave Man United even though he had been given the green light.
Erik Ten Hak is no longer giving him the chance to be a key player in the team but he says will try to give it a chance if he can get back to the form he used to have at Leicester City. Personally I doubt Harry Maguire will perform as well as before if he stays at Man United because he is mentally disturbed due to the pressure from fans and other players at the moment.