Honestly it's probably because you are likely in the minority in wanting this, at least according to the car manufacturers. Cell phones haven't had audio jacks for a few years now. Most iPods are in junk drawers, dying long and slow deaths. Take a look around the next time you are in a crowd, the people with headphones on, like 90% of them are going to be airpods or other Bluetooth style headphones.

Ain't saying I like it either, don't get me wrong, but I imagine that's probably the logic behind it.