Then someone will know where your car is at all times, and probably who you are... and that is monetizable (not from you).

If you do not believe that is already true on multiple axes, you are probably mistaken. The combination of automated license plate scanners, phone beacon data, and behavioral metrics make that relatively straightforward to get, in aggregate.

I worked on a project where we could tell how many users were in a given store at a time (historically, not realtime) based on wifi traces, mobile data aggregation from carriers, and bluetooth pings. We could generally back it up to even general demographic data like how much disposable income the users were likely to have. Interesting project, deeply worrying how much data is running around out there.

Google maps is free to use so obviously I'm the product Google sells. I'd say I'm getting a fair deal letting "them" track my location. (Why does nobody ever complain about them insisting on gender neutral pronouns? They must be very powerful.)

Often times, even if you pay, you're still the product a company sells.

Someone probably already does. Every car sold within the last 20 years has tracking electronics and can be remotely crippled or shut down.

If there is someone who wants this data, I am happy to sell... no need for a middle man.