It seems ironic to me that I've bought multiple cars from a dealership and I can't get them to update my email or postal address after well over a year. They apparently don't want to send me ads.

I know exactly what you are talking about. When my wife bought her last car, I stopped by the dealership after work to cosign all the papers and for some reason they entered my phone number into their database. They started calling me and each time I would tell them to call my wife because it's her car. It took probably 10 or 12 discussions with various people at the dealership to get our record updated. The general manager seemed to be as frustrated with their system as I was because he had to deal with me asking him over and over to fix the problem.