Why though? For a business owner I can’t imagine a better situation than his workers working for free and having to do 16 hours a day under pain of death. This probably wouldn’t work with 80% of the populace enslaved but would work very well with 10-15% enslaved.

Slaves aren’t free.

You still need to feed them, clothe them, and house them.

You need to do basic medical care.

And now you have the problem that most of them would happily murder you in your sleep/if your back is turned, or run away never to be found. So the tend to be a pretty big security risk.

Oh, and also they’re slaves so good luck getting them to care about their work - way worse than a typical new hire retail employee even. So you need to do heavier supervision.

Oh, and you had to pay to acquire them - instead of give them an offer and pay them after they’ve worked for you successfully. So add that to the ‘risk’ pile.