48 volt car accessory systems?

A few years ago there was talk of raising the standard for the voltage in automobile systems from 12 to 48 volts. I can see advantages,but not any real disadvantages, so why hasn’t it happened?
I’m not asking for opinions, I’m wondering if there are practical considerations I’m not aware of.

As I recall, several significant items, including light bulbs & microprocessors, really work out better at 12 volts. Thus there would have to be either a secondary 12V system or a stepdown transformer. I’m sorry I don’t have more details, but I’m pretty sure it turned out to be a bigger pain in the butt than was first expected. I’m not sure the notion has been abandoned, but it seems to have lost steam.

I agree that 48 V would be superior.

The car manufacturers purchase most of their electrical devices from third-party suppliers, and everything would have to be redesigned and tested from the ground up. This takes lots of time and money. Mostly the latter. Unless there’s pressure from a state government or the federal government to do it (efficiency standards), there is no reason for a car manufacturer to invest lots of money to do it.

The higher voltages are coming, not just in electrics or hybrids either.
Manufacturers seek to remove mechanical boost items from the vehicles and drive by wire so to speak. The power steering, brake boosters, and water pumps would be electric. The extra voltage would be an advantage.