That’s interesting information, yet perhaps not so easy to interpret. A $100,000 outlay for, say 20 years of labor, is only $5,000 per year. There was also food and housing. It would probably come primarily from slave labor, but would reduce work hours dedicated to the production of revenue from the sale of cotton, etc. All in all, I think we are talking of outlays that are far less than the current minimum wage.
I have an in-law who received a bonus last year in excess of $100,000. That is on top of his annual salary. He is an engineer who likes his work. I’m sure his employer knows he likes the work, but they’ve decided not to rely on intrinsic job satisfaction to keep him happy - and working for them.
Consider $100,000 as the NPV (net present value) of a worker, where you have to not only consider wage outlay as a forgone cost, but the subsistence of the worker. That is, your benefit from the worker is a stream of “revenues” of wages-subsistence. And you have to figure in prevailing interest rates, which ran around 6%. I figure in 1850s terms we are talking of an implied wage more like 15K. And this is for a manual worker with very little benefit from productivity enhancements, a sub-third world level in modern terms. That’s expensive labor.