I'm a millennial, I've been using CarPlay since 2013, and I will NOT buy a car if it didn't have CarPlay. In fact, I love my 2020 Mercedes because it utilizes the full 13" non-touch display for CarPlay and you can use voice control to send messages and request songs. The 2021 and newer models use touch screen and do not utilize the full display for CarPlay, and it honestly prevented me from upgrading to a new car.
100% of my Gen-Z co-workers and friends clearly stated that they will look for a car with CarPlay. Aftermarket integrations aren't worth it. People who own Tesla cars complain the lack of CarPlay, including my brother.
CarPlay just makes sense.
GM isn't what it used to be.