As far as Philly is concerned, Asians as immigrants are fairly upwardly mobile. If the city doesn't have anything to hold them in town, they will likely move to the suburbs. This is clear from the stress most Asian-Americans put on education. Of course, Philly is not the only city to have to deal with this, it's more of a city-vs-suburbs issue. In past immigrant waves, people would settle into the city first because that's where the jobs and industry were, and that's where more of their own kind were... not so, in today's world. Now, more jobs are created in the 'burbs, and immigrants (Asians, at least) might first come to America and land in a city but they soon move out to suburbs for safety, education, taxation issues... perceived or real.
"The only difference between the Republican and Democratic parties is the velocities with which their knees hit the floor when corporations knock on their door. That's the only difference."
- Ralph Nader