Science and history programming is sadly low brow. Netflix had a 12 part series of lectures from Neil deGrasse Tyson that were refreshingly thorough and weren't watered down. They didn't seem to have it licensed for very long as I think it's already removed from their library.

Regarding stuff that seems to be geared towards 8th graders, that's just what some people want to see and you couldn't force them to watch anything with more substance if you wanted to. Not everyone has to enjoy the finer things. I don't think it's that they don't know there's a difference. It's just boring as all hell to most people.