I just don't see this issue getting much traction until something really bad happens to a large group of powerful people. But even then it may not come to light

I just don't see this issue getting much traction until something really bad happens to a large group of powerful people. But even then it may not come to light as said people will cut a deal with car companies to exclude them from telemetry sighting "national security". They of course won't publicize this and when it inevitably becomes public they will just shrug. It won't get traction for the average person because the immediate effects are positive (lower insurance) and the dangers are very theoretical (a bad actor knowing where my car is). People are much more concerned about the near and present danger of bad actors hacking their financial accounts and stealing they hard-earned money.