You do know that state-issued ID cards exist, right? They usually just say "Identification card" or something.
Yes, they look similar to a driver's license card, but so what?
We have ID cards. We have driver's license cards. The latter is so ubiquitous that there's really no reason to require drivers to carry both. Just allow the second to be used as the first. AFAIK, in most states, they're both issued at the DMV (or your state's equivalent organization) anyways.
I'm just really struggling to see what you're trying to get at. Your question is posed in such a way that I'm interpreting it to be an attempt at some sort of "gotcha" question.
They are often called driver's licenses, though, because it is so common that the official state issued id is a driver's license. In less formal language (in my experience) "identification" usually means random student id or bus passes or any picture id would be ok while "driver's license" means official state id or military id.
