Federalism in the US, a large section of the population that has no intent to travel outside the country, and general suspicion of the Government in a lot of states means that there is a patchwork of different IDs with different requirements, all of which are perfectly valid for their own jurisdiction. Real ID is just a way to set a basic standard for this kind of ID that will be required for (mostly interstate) air travel.
A better analogy for you might be a European ID. Get back to me when you can file taxes and access medical records anywhere in Europe using the same ID. (I half expect someone to pipe up saying that this is indeed possible and make me eat my words.)
