There's a few car dealerships that still use databases from the 80s. As for why they haven't migrated, I'd guess must be reasons I'd assume at this point it's a choice they have made
If it's a new car dealership, though, they're surely using (relatively) modern systems as well, as there's no way they're using an old DOS system to communicate with manufacturers to order cars, file warranty claims, submit financial reports, obtain service information, …