This is a reason to buy a shirt, nothing more.
Professional players make their decisions based on a number of factors. A good percentage who do not do it for money, do it for a few reasons, primarily his value to the club, how much the club values the player; "our true number 9, our starter for twenty years" sort of thing. The other could be winning, but he obviously didn't do it for that. The last is sometimes the most important and that's club culture.
If you pay 90 mil for a guy and sell him after a year, your club is a joke.