Setting them free would be promoting them to a liveable wage.

Which would permit them to save up some cash, which in turn makes it possible for them to advance their education, move to a different country if they choose, or just save up enough to live on for a while and leave.

But that's not profitable. Master would have to "train" somebody new.

If your employees feel like slaves there's nothing you can do to change that except pay more and improve the working environment/hours. Also they won't tell you if that's the case, they want you to free them.

If you're a small business owner odds are you pay your people well though, unless your just starting and struggling to become profitable, in which case you're out there pulling your weight with them.

I can think of one decent paying position that doesn't require a bachelors. Mailman. But competition is fierce for a job with the USPS.