The ultimate cause of white flight was the great migration of blacks from the South - which was encouraged by the industrial expansion of the North that had been started by massive immigration.
I'm confused. Earlier you said "Historically, immigration caused widespread social problems in US cities." Now, above you say that massive immigration started the industrial expansion of the North which encouraged black migration from the South, which caused white flight. How dare those darned immigrants causing the industrial expansion of the North!
Or maybe we just shouldn't have been so open to MASSIVE immigration. But then no intense industrial expansion, and no expansion of the pockets of profiteering industrialists. Absolutely correct.
As I said above, it's all connected.