These chips are not fungible commodities. In the automotive space chips are selected based on a number of things including feature set - how many CAN interfaces does it have, how many GPIO, how many PWM, what kind of brown-out handling, what voltage range, thermal rating, etc... Software is then written where a portion of the code is specific to that chip. There are cases where an OEM get really good pricing on a bigger (overkill) chip and helps a supplier get those at good prices too, but usually they just beat you over the head for the lowest cost. Even if everyone adopted a few larger parts and used just those, they're still usually made by a single chip company.

This doesn't exist now for the same reasons it probably wouldn't work in the future: You can save significant amounts of money if you cut the pieces out of the "standard" that you don't actually need. Chips are cheap to make, in bulk. It's almost entirely a fixed cost/area. That's the magic. So, it's almost always cheaper to make a custom chip than to pay for some bloated standard containing large sections that will never see power, especially when chips are something like 40% of the BOM, for modern cars.

No knowledge of the automotive industry, but that sounds impossibly high.