It's funny and slightly ironic how Sanchez has been pining for a move to a club where he's guaranteed trophies while also getting the best out of him for the latter stages of his career (i.e. City). Then United came in and ruined everything by making obscene offers and making City pull out, but he burned significant bridges and it came down to staying at Arsenal, who are at the worst they've been, for even longer, or going to United. I mean, if you're a player like Alexis Sanchez, surely you can't look at Mourinho's United and think "that's the team I want to play in."
Could have gone to City, score shit loads and win the league, maybe even the CL. Now he's going to play wing-back and dance with Lingard. Good money though.