To be fair, colour photography and film did already exist in WW II. That's not to say that black and white should be 'retrofitted'. It borders on historical falsification.
Segregation policy (also known as apartheid) has long been abandoned - because it didn't work. The fact that people tend to 'segregate' into separate communities is not the result of a nationwide policy. Rather, it's the result of, being conservative, tending to stick with what they know.
The classic case of segregation policy is, of course, South Africa. It didn't work, simply because you can move people where you please, they still need to go where there is work. In essence, apartheid was a farce. So, you can build billion dollar walls all you want, that doesn't stop economics from working. (Something which you might expect a billionaire businessman to understand.)