For the most part, it’s believed that carmakers are doing way with Android Auto support simply as a way to expand their control over user data. Because Android Auto utilizes your phone’s connection, all of the data that runs through it goes straight to Android and the phone manufacturer. So, by utilizing built-in systems, the car manufacturers would indeed be able to collect more data about how you use the systems in place, while also possibly getting more money out of you through subscriptions.
Rent seeking behavior. They want subscription revenue instead of wanting to deliver what consumers want.
You are unfortunately correct.