Can you not just physically disconnect or shield the network antenna (assuming you own the car outright, i suppose if it's financed it might be trickier to do that legally)?
The same pipe that exfiltrates tracking data is bringing in the data for all the connected features of your car. That would include things like satellite radio, onboard navigation/GPS, software updates/recalls, and concierge/safety services (e.g. OnStar). In some cases, the same data is being used to both track you and provide the service, because the collection is happening somewhere on the backend. I wouldn't be su…
Which is very worrying when you stop and think about it. If anything that actually matters is reliant on anything not travelling with you then that can not be a good sign for the safety and security of the vehicle. For one thing any vehicle that has any open incoming connectivity of any kind immediately has an attack vector for malware. And in this case that could literally be a matter of life and death and it could literally be used to attack thousands or even millions of vehicles simultaneously.
The closest I can think of to any legitimate phone home feature is an automatic emergency call function that is triggered by a collision or theft being detected. But of course it's very easy to specify that those features may only be activated from the vehicle side and may only be used to contact emergency services.
Anything else like GPS or infotainment does not need to be integrated at all with the essential vehicle systems or emergency communications functions and can be subject to the usual safeguards like any other device - including an off switch if the owner chooses not to use it and requirements to opt in for any potentially intrusive behaviour.