What if they are forced by governmental order to hand over their data?
"Why is it acceptable on any level for my car to become a spyware device on par with Facebook, when I paid an enormous sum to be its owner and controller for my own benefit, and not to become a residual profit stream for ${CAR_COMPANY}?".
What's a dossier like that with on the market when it includes location, Bluetooth IDs of all occupants and private conversations? $5/mo? $10$?
(not to excuse ISP data collection, but implying that a car is as critical for network access as an ISP is nonsense)
Signal for example, is also subject to US law. They can be compelled to reveal everything they have in a person. Which they happily do: they hand over a page with the date of account creation and the day it last connected. Which is all they have.
Don't collect information, and you don't have a problem.