Earlier quoted context omitted.
Isn't that kind of the other way around? Ignoring the obvious moral question, in a primarily agrarian economy slave labor is useful because it's relatively easy to control and there is no need for specialization. OTOH in an industrialized society you wouldn't want slaves even if you could have them.
>OTOH in an industrialized society you wouldn't want slaves even if you could have them. Really? Leaving aside the moral issues most associated with slavery specifically, there is a huge demand in modern industrialized society for all sorts of low cost human labor. If middle class-ish people in the West could hire more people for the equivalent of a couple dollars an hour many would absolutely do so.
Cleaning houses, mowing lawns, sure. But you wouldn't even get as far as a taxi/truck driver, which is one of the least qualified jobs today.