Natives were never enslaved. They were disenfranchised. Stone age tribes that hadn't even invented the wheel could have never hoped to resist the spread of civilization. It started in the middle east over 6000 years ago, and has been evolving and spreading across the globe ever since, setting up franchises. When one franchise fails somewhere another takes it's place and the idea lives on.

I highly recommend reading the writings of Abdullah Ocalon on this subject.