I’m happy to merit your insufficient-car-brains certification :-)
What quite do you mean? That horses weren’t used in the same way or for the same demographic as cars are now? Sure, and you also don’t refill them every 200 miles from the nearest highway hay-station. (Well, kind of…) But there were still horses clustered in many cities for a lot of the time, right? Where now there are cars? And as transport such as did use the one mainly transitioned to the other. I don’t suppose there’s hard, quantitative data on car-induced vs horse-induced deaths/injuries within cities at certain eras, but maybe someone has that data somewhere!
Actually, to go another step from your point: I suppose if cars, in their same number and usage, were traded for horses, then besides the epic problem of feeding them all, many cities would be far more dangerous now from the great horde of horses marching through every day!