[gruez]

Profitable/unprofitable is the wrong way of looking at it, because it implicitly ignores opportunity costs. Putting your money in a savings account at a big bank might be "profitable" in the sense you're getting paid some meager interest rate (eg. 0.1%), but it's definitely not the best option, like a money market fund or equity ETF. What OP probably meant was that slavery was worse than the alternatives, like putting your money in a savings account with meager interest rate.

[chadgpt3]

Then why didn't slave owners sell all their slaves and put the money in savings accounts?

[tonfreed]

I think you're missing the point OP was making. He's saying it's profitable but not optimal, those who recognised that quickly outstripped the slave owners in wealth.

I could ask you about your spending habits and why you don't pump all your money into an S&P 500 ETF, but that's ignoring time and consumption preferences you have, as well as perceived opportunity cost. It's not a useful observation to make at an individual level.