So much ignorance it hurts. :/
Apple's AirPods are gold standard in wireless headphones....and of course Bluetooth based. Apple bought into Bluetooth very early, about 16 years ago. They integrated support into OSX even before Microsoft added it to Windows (before that your device had to ship it's own Windows drivers). Their standard keyboards and mice have been bluetooth for years now (although the keyboard retains the option to use it without BT while charging on the hardline via USB). So "Apple does not desire Bluetooth to exist" is mind bogging lunacy beyond what I'd even expect from you.
Inter-vender bluetooth can be dodgy at times. It is hardly an Apple limited phenomena, even with Teslas.
What there is an issue with generally on iPhones are 3rd applications that want/need to assume they continue to run in the background 24/7. Because iOS is heavily tuned to squeeze out everything it can from the hardware and battery, it tends to be fairly aggressive about swapping out inactive applications from RAM. The bypassing of that is treated as entirely internal, it's a highly guarded facet because letting a bad actor in jeopardizes the otherwise high stability of the platform for users. It's very clearly a trade-off but one that it's customers rely on. *shrug*
To bypass that aggressive putting to sleep algorithm and guarantee being able to operate background a company has to solicit Apple's generally opaque iOS management team. As far as I've been able to gather Tesla hasn't gotten approval for that yet. I don't know if they've even tried but Apple's process on these matters tends to be fairly lengthy and particular. On the flip side they tend to be rather PR aware so while Tesla's market isn't particularly big they seem like a prime territory for Apple to support due to Tesla's cachet (and as far as known Apple's interest in automobiles has been shelved). So barring individuals getting into inter-company pissing matches over who knows what (prior Apple Car stuff or employee recruiting?) it seems likely that Tesla will get a backdoor key at some time.