Debt is much more effective than slavery. Unless misery is your goal, you can do a much better job at extracting value from people and keep a population working for your benefit with debt. It has a way of making both sides feel like what is happening is “right” while having the same effects.

I guess we'll see. The test is in front of us. There are nations using indentured servitude and de-facto slavery and there's the Free World. If the other guys are better at it, let's see them beat us.

I'd rather humanity survive through slavery than be extinct through freedom, but I don't think I need to make that choice since I think free people self-organize into more resilient societies so long as they do not assume too much load of taking care of the non-adapted.