Really?
Gallagher went to Palace on likely a third of that and vastly improved their team. Lingard himself went to West Ham on nowhere near that with the same positive effect. I doubt Eriksen was on much more than £50-60K and turned Brentford into a much better outfit.
With a poor team as a starting point it shouldn’t logically cost high salaries to improve it. Conversely, if it were a really good team and you wanted to improve it then wages in that bracket would be required most likely.
Lingard is definitely on about £150kpw at united and he'll be wanting more of the same at his new club because of moving on a free.
Lingards time at West ham is more the exception rather then the rule over his career. Looked like a player playing for a move and when he didn't get it reverted to type.
I expect him to continue his united form rather then his west ham form, when he signs a fat new contract at whichever club is stupid enough to sign him.