Because it is easy.

That is it. It is easy and cheap to make cars connected because of abysmal lack of regulation and the massive IoT chip industry

Integrating wireless radios into products is standard by now and chips required to do anything but 5g are extremely cheap. GPS is also dirt cheap. The biggest costs by far are design hours and certification.

Then they can make money because of the software "features" that only take man hours to develop as well as sell your tracking days after the fact. Together with the fact that if the market says that most people want those convenience features and couldn't care less about their valuable data as we have seen through every tech industry, there is little reason NOT to put in those features, especially when it enables OTA car firmware updates also.