These invasions are really more reminiscent of the “barbarian” invasion of the Roman empire. Although there were certainly barbarian raids, most of the Roman territory was conquered by tribes coming from north of the Danube and east of the Rhine and creating enclaves and settling in the border regions. These tribes had been in turn displaced by other peoples migrating from the north and east.
The key is mass migration, concentration through the creation of enclaves, and then semi-autonomy by gaining the reigns of power via the political process.
But, there was no George Soros to pay for the buses and food back then.
Same thing happened in Fiji. Too many Indian servants to wait on the Brits. I guess the natives didn’t know the concept of work.