Amorim is a business man, and wants to show his skills and experience to the world that he knows how to revive a club that's is stumbling. He did it in Sporting and can also do it in United, if he gets his desired players. Amorim is still young and has more talent in him, he needs more time to transform the team and we can start seeing good results from next season.
I also believe with the talent and skills that Amorim currently has because his experience when coaching Sporting Lisbon has been very proven so that he can create a greater tactic at Manchester United for this season, especially in the second half of this season. Because Amorim does need to get some new players who are better so that Manchester United can rise again from their slump so far.