Pointless memo to the car manufacturers:
The drivers' and passengers' devices will be newer, probably more powerful, more likely to have security updates, and have a greater chance of containing apps and data that the owners actually care about.
You are hardware manufacturers, you will fail hard at producing software people want to use.
If you wanted to do something useful, concentrate on allowing the vehicle screen/speakers/inputs to serve whichever device(s) the driver selects. Provide power, pointer movements, keystrokes, and sensor data. Accept video and audio.
For comedy value, submit your software to Google/Apple/Whoever and see how many people actually use it.