There exists a floor to how "idiot-proof" Motor vehicles are since they do require a skill test and a licensing protocol to legally operate that do weed out some number of humans not competent enough to operate them (and even beyond that insurance qualifications can weed out some more: crash or commit infractions too much and you lose and/or get priced out of your ability to legally drive). And rightly so due to the unique hazards that they pose: but for want of those things one may easily still have to try to support their software for users incapable of gainfully handling a motor vehicle.

Automobiles and the international road network have also had well over a century to standardize themselves over a glacially slowly changing set of expectations while we're writing drivers for 400GBE chipsets that only got invented last Tuesday and building agent management harnesses for styles of neural networks that literally weren't even a twinkle in the milk-man's eye yet as recently as fidget spinners being in style.

Sure software moves fast, but it also moves slow.

How many bad UX redesigns do major desktop/phone OSes need for their phone/text/mail/photos apps?

We're at least 30 years into email apps for example, and yet the UX changes year to year for.. reasons.