The whole tax argument is often flawed on both sides. People either try to make too much or too little of it.
It does play a part in decisions for SOME players and in certain circumstances. Sometimes that number can be offset by other business ventures or personal factors. But its also 1 of who knows how many things that go into a decision. Do you want term, do you want to win, do you just want to get paid, do you have family in the area, wifes family, do you love the beach/mountains/desert/big city, is it a home town, do you have good friends already playing there, do local politics matter... list goes on.