I respectfully disagree with your initial point regarding "can" versus "what they do."
Even if a company provides assurances and pledges never to mishandle your data or use it for nefarious purposes, there remains a risk that your data could still end up in the wrong hands.
Would you sign a paper saying I can come into your house unannounced if I suspect you stole something? If you do not steal you have nothing to worry about
On the second point, sure, but so we have knowledge of what, how, and for how long, the carmakers are storing?