Car makers want vertical integration. They want CarPlay gone and their own system in. I personally will not buy a car without CarPlay.
My phone knows me on a deeper level than my car could ever know me. I want it to be the center point of my experience while driving.
I use Android Auto, and it just seems like a no-brainer: I already have all of my settings and contacts and podcast/music apps and downloaded files etc. on my phone... So why would I ever want to maintain a parallel inferior system chained to my car with a smaller software ecosystem and a prohibitively long/expensive upgrade cycle?