Certainly these improvements led to overall population growth, which accelerated over a few centuries. But the pattern that richer people had more kids than poo

Certainly these improvements led to overall population growth, which accelerated over a few centuries. But the pattern that richer people had more kids than poor is a different thing. I believe this persisted until Victorian times in England. The US frontier was a gigantic anomaly in other ways, and could be in this way too, I don't think I've seen data.