I have to say, considering how Google half-asses things I'd have no confidence in this product. That said, a half-assed effort by Google is still probably better software than the full-ass software effort by carmakers.
My real dream is to get these things fully modular. Let my lift up the touchscreen to access a cavity where a little infotainment-SBC is wired into a couple of USB ports and a mini DisplayPort. What's it got to run? Audio, touchscreen, GPS, phone-over-Bluetooth? That stuff is well-known. Basically the only place where I expect standard interfaces to fall on their face is climate control. As an API fallback, have the built-in car-computer run a private web-server for controlling the car's non-standard hardware. Then just have the SBC use a browser for those screens. Only API needed is "what URIs do I show for what features like climate or trip-odometer or whatever screens can't be standardized at the infotainment level".
My worry is that google once obtaining the monopoly/duopoly, will do what they did with android, kill all of its "open" values in the name of security and push their own services
Car components talk via CAN bus. There are many aftermarket head units that includes CAN bus support and has presets to talk and retrieve information from multiple car models (climate control, lights, speed, engine status, etc). The problem is, most cars manufactured in the past several years don't allow aftermarket head unit installation anymore, so you're basically stuck with whatever entertainment system the car manufacturer put in the car for the rest of the car's life.