The thing that is never asked is why where the widget factories of 1880-1920 built around the Great Lakes instead of the South. Were there no men in Alabama or Mississippi in 1896 to work in a factory? They only appeared in 1966?
I think the explanation would be that before ac, you’d have too many workers shuffling along—if not outright keeling over—in the summer heat. Working in the fields was probably not as bad as an afternoon cooped up in a steamy factory!
The climate played a part, but the infrastructure made a difference, too. Up until recently, Southern infrastructure was heavily geared towards an agricultural econonmy- that is, the roads and rails were designed to ship agricultural goods from the farm areas to the ports for export. The North’s infrastructure was based around moving people and goods from, say, the coal mines of West Virginia to the steel mills in Pittsburgh, then to other cities for use in industry or to ports for export.
The South’s approach to infrastructure was one of their major problems during the Civil War, BTW.