> If you were going to design a new car electrical architecture from scratch today, you would have something like a 40-60V system with a centralized controller (or pair of controllers in a safety redundant configuration).

Aircrafts historically been using high frequency AC, on both sides of the iron curtain (as both sides were copying each other.)

Old analog instruments actually benefited from AC availability.

And when SMPS were big, and heavy, transformers were much more reliable, and smaller (and they are still are, depending on the frequency)

3 phase power was also giving some interesting cost cutting benefits at the time