People join the team more likely for long term success (the team with a bigger budget is generally the team with more chance obviously needing to account for current squad quality).
Its why kante joined chelsea. Leicester were top dogs yet he still chose to move to lowly 10th placed chelsea.
Its why someone would choose real madrid over atletico.
Sure united are down in the dumps this season but they have won more trophies than you in recent history and they finished above you last season so actually until this year they were the better side