That income tax thing is very important of course. But you can also buy that out, the Yankees and Dodgers manage.
Seattle's great, I live in the NW. But do you think Robinson Cano cared about that? No, he got paid, and the two crazy mansions he bought with the $ are both in the DR, not Bellevue.
Despite its problems Philadelphia has been in the midst of a revival, especially for young people. Pat Burrell and those Flyers guys had partying in Old Town; today's similar young baseball player might be more interested in eating at Zahav. And Hamels, Utley and Lee all enjoyed having a family life in a city - and in a way that is much more manageable (and cheaper) than NY. Many Phillies also find the team to be a fit because they live in Tampa or Orlando.
And Yu Darvish loves Arlington.