The middle class in the US is slowly becoming more and more racially integrated. More and more young people go to college and then work in increasingly racially integrated environments.
The primary areas where we remain segregated are in housing/neighborhoods and in religion.
I'm fairly convinced that if nothing changes the white, middle-class church that has been the foundation of US evangelicalism will be irrelevant within a few generations. My grandchildren will enjoy the diversity of their school and work environments, and will look for that in their church.
It's also interesting to note that while white evangelical churches in America are for the most part declining in attendance over the last decade (with notable exceptions, such as my own church), attendance of multi-racial and non-white evangelical churches (particularly Asian, African, and Latin American immigrant churches holding bilingual or non-English services) are growing.