Not quite, that doesn't allow integration with steering wheel controls.

Sure it does. Even headphones have controls built in to the cable.

That is not standardised across different headphone manufacturers and often doesn’t work. It doesn’t work at all on cars.

Analog protocols are not a good idea for this. Digital with a decent protocol is much more reliable, whether wired or not. In practice, the best option is either wired CarPlay/Auto or bluetooth.