True wireless earbuds don't necessarily have to end up as electronic waste when their batteries reach the end of their lifespan. Fairphone demonstrates this with the Fairbuds 2, whose batteries can be easily replaced. The earbuds also offer active noise cancellation and support for Sony LDAC.
Phone thickness is the excuse, but adtech is the reason. Just look at how camera lenses are handled.
Forcing everyone to use Bluetooth means you’re more likely to leave it permanently enabled. And that means a lot more data for adtech. All those beacons in shopping and urban areas make population-scale measurement trivial.