Cars 20 years ago didn't have realtime traffic on big touchscreens that you can use to look up your destination and plan out a route that also lets you schedule fueling/charging stops, oh and also stream humanity's entire library of recorded music, books, and podcasts. It's a tradeoff that the vast majority of people want.
But almost every smartphone already has those features, they work fairly well, and it makes more sense for a phone to have those features than a car. (Because sometimes it's useful to know where traffic is when you're not in a car, and stream things while walking around.) It doesn't make much sense for each car manufacturer to replicate everything if they can figure out how to connect a phone to a car, and borrow the phone's features.
