Your last paragraph is what's ultimately gonna kick this thing off, the noticeable decline in living standards amongst whites, especially working class, while more subsidies and preferential treatment goes to non-whites.
I've talked to complete normies who see that the system simply cannot continue much longer. The masses of retiring baby boomers over the next decade will be the breaking point.
On the other hand, it's completely possible Jewish billionaires like George Soros will simply fund "colored" revolutions, like in Ukraine and Syria, in the United States. BLM might be a test run for something like that.