American homes are typically 240vac, 60hz, between both hot lines. (That's what feeds car chargers, baseboard heaters, dryers, and stoves.) 120vac comes from taking one of the hot lines and one of the neutral lines. It allows a home to have two voltages without a transformer.
I have no information on the voltages used in the early AC grid but. In the US distribution is 15kV. So the turn down even for 240VAC is 60 to 1. Some experience with pre WWII house wiring says 20-50 amp service was common. The difference between the economics of AC vs DC might have not been so stark when people were running a couple of 60W lights.
[1]Seen three old houses run off two 20amp fused circuits.
I understood it to make transmission easier but the US would face that problem at least as much as anywhere else...