but this seems to suggest its becoming the way many american cities have become... complete flight of wealth groups into complete segregation, complete flight of ethnic groups into segregation... and no easy ability to intermingle... all like-minded people with no interaction from anyone else.

Just look at a prison yard. People separate into their racial/cultural groups. It's anthropological. The only exception is when you are super good looking like me and women from every culture swoon at your feet.