In my opinion slavery doesn't make that much sense financially. You have to pay a significant price to buy a slave but there is going to be some who die or or become disabled before they produce enough to be worth it. When that happens it'd be like buying a car and losing your investment entirely after only a few years or even a few months. Then on top of that you have to pay to house and feed them, and you need to secure them so they don't either run away or try to kill you.
I understand that at larger scale they can combine some of these costs, but it still seems more logical to me to just pay someone peanuts wages in those times and let them buy their own food, housing and healthcare when they go home. Yet my understanding is slave owners did indeed get hella rich off the practice and beat out the people doing it the wages way. Why was owning them instead of just paying them so valuable?
u/freedmenspatrol breaks this down in an answer here: https://www.reddit.com/r/AskHistorians/comments/8gjzij/if_a_single_slave_cost_the_equivalent_of_57k/
I think you vastly overestimate the cost of feeding and housing a person whose human rights you don't respect. For starters, they'll do much of it themselves out of a desire to not starve and die. The slaveowner mainly just gives up some space which is, in a way, a cost, but a relatively meager one. Some cheap clothes (occasionally), whatever extra sustenance they can't grow themselves but need, and that's it, for a lifetime of labor.
You hire a worker, even a poor worker, they're not going to want to work long hours at backbreaking labor for a nearly starvation wage. They'll just go somewhere else. If there's nowhere else to go they might make more money begging in the streets of the nearest city. But the slaves can't leave.