Agree above Electronics is the biggest one. older generator, some starters (other than direction of spin which could be set) and lights did not care. (other than the age old arguments aka bar fights found all over the web for what corrodes what does not)
the biggest reason the moved to negative ground was electronics and the money that is around that. The big three and this is a generic three had to agree on a standard. (in their respective countries) hence why north America when negative ground.
and England and a few Europeans stayed with positive ground. The standardization allowed for a lot of creature comforts without having to chase manufacture part specific (they did not have to either with sourcing vendors).
I have fried a few radios back in the 80s when a few friends had some older British cars and we forgot to check which ground it had.
Google positive ground vs negative ground and you will not find much of a one size fits.
But if you dig deep enough I bet you find money is the answer.
