> Slaves can build tractors.
I doubt they can do it well. Machinery is hard enough for enthusiastic people who are being showered in money.
> It's my contention that had the South been able to hang on to slavery, it would have found ways to work it into niches it never filled in the real world.
Perhaps. My experience is that skilled industrial jobs are hard. Even in the time of Henry Ford, high wages had to be paid to attract good enough people. If slaves could get the job done, then auto workers at minimum wage could do it, which seems absurd to me.
> In a Christian nation, slavery either doesn't exist or is infinitely gentler than what actually occurred.
Southern slaves were not treated nicely (slavery, duh), but they were treated well in comparison to many other examples of slavery. Elderly, worn-out slaves were a reasonably common sight, despite the fact that their economic output was near zero. Slaves were given the very important job of child care (creating the Southern accent in the process), which is not a job given to a sullen, mistreated drudge. Compare this to the Arabs, who use slaves completely up and plow the bodies under as fertilizer. (See Dubai for a modern example.)
> This is an interesting idea. Who argues that?
TVA, Oak Ridge, Huntsville, and so forth. Huge amounts of resources were poured into creating technology projects from scratch. By the time of Apollo, Southern senators were good at bringing home the money and economic development.