Nothing has changed for United because even though Amorim came in and changed things for the better, in the end it still failed.
In the Premier League itself United are like a mid-table club and it's quite easy to beat them at home.
The fans will never care if he leaves or not because United are so far behind the competition and they are having their worst season probably at the moment.
The only impressive thing in the Europa League is that they are unbeaten so far but no one knows what will happen to United in the last 16.
I highly doubt Manchester United will appreciate Amorim's achievements in the Europa League, unless they can become champions, which I doubt. They have terrible results in the Premier League, Amorim can't fix that, and one transfer is clearly not going to change the team. As for Rashford, let's see what he does at Aston Villa, but he has really become a lazy player, he needs a lot of work to change.