So if you got two job offers, one paying 100 K a year and the other paying 120 doing the exact same thing, you wouldn't take the bigger offer because "20 k doesn't make your life that much better?". That is failthought.
First off, it's not necessarily the salary, but the prestige and respect that comes with making money. And there's the fact that it's a $20 million dollar difference. Are you people serious?
Sometimes a player will bypass the extra money if they really like a place (Lee, Teixeira) but Ellsbury owes nothing to the Boston Red Sox. If he really likes the place, he'll find a way to stay, but let's not pretend that in most circumstances you wouldn't take the paycheck that's twenty million bigger too.