Amorim would have sold all the problem players like Mainoo, Garnacho or Zirkise a long time ago but Manchester United have big money problems right now. It is said that the team is hundreds of millions of pounds in debt and in order to somehow fix the situation, the club has raised ticket prices for fans. So for now Amorim has no good solutions and until the end of the season will have to play with the squad that was picked up by Ten Hag. I think that now Amorim regrets that he left Sporting, because the problems there are less than at United.
Manchester United is having no financial problem or debit which creates problem for them even they spend huge funds for few players which fail to perform as expected but now Amorim doing few good things and offloading players which was the problem which is big change with this now things can take changes in the future.
Even still it's not easy for him to work on solid strategy which keep team in good position but as he is working and doing overhaul this is positive thing happening Eric Ten Hag spend huge amount on many players but most of them were big failures. Currently, Manchester United have good thing they ended in top 8 which give them good confidence and this could be good motivation for them as well now they needed to work on their performance in Premier League which is more important and could be good for them.