Perfection is the enemy of good

It's because electronic controls are cheaper (and more reliable) than mechanical. Also, because it's a lot cheaper to implement a poorly-understood problem in software, not hardware.

One just has to look at routers, which have flipped between being software controlled, and hard coded in FPGAs etc, several times over the years. Every new generation is implemented in software initially for flexibility, then as the problem space became understood, was moved into hard-wired silicon for speed.

That trajectory occurs again and again - we saw it in printers with that abomination called GDI/WinPrinters (and I think I've just bought a modern incarnation thereof :-( . I'm sure other people will have other examples.

Cheers,
Wol