Or car markers could just stop being stubborn and greedy with their proprietary trash and just support Car Play/Android Auto. That way the car acts as a dumb terminal for displaying stuff from the phone and nothing is actually stored in the car.
But no, gotta charge hundreds for in-car map updates (that only get updated as often as you purchase them) and radio/traffic subscription that mobile apps charge a fraction of and always up-to-date for as long as you keep the apps updated.