I highly doubt that America would reverse decades of progress in equal rights and revert to segregation. Why should they, when the free market economy can do it for them? Look all around you. Racial discrimination isn't as overt any more because bigots have learned they can achieve the same homogeneity by the placement of expensive homes and shops, where it's most white people in the upper income brackets who can afford it? And if you do get a couple minority families in there, hey, no big deal, it just helps you to claim that you're diverse after all. But no, the government won't ever revert.
America has learned that segregation does not pay, so now we have desirable and
undesirable school districts instead of good neighborhoods and ghettos. Americans
have learned to discriminate in subtle ways. Generalizing wildly, we expect all
Asian Americans to be smart, all rich Whites to be heartless, and all poor
white people to be lazy. Mexican Americans all work incredibly hard, and
African Americans are all naturally musical. We have not given up stereotyping people
we do not know and will not know because they live elsewhere. We have simply
changed our stereotypes