That is not to say that education and skill is not required to effectively teach students. I had some really good high school teachers that did a great job of making things stick.
Thing is, with any educator (be it high school, college, or technical trade skills) you need more than knowledge about the subject at hand, you also need to know how to deal with people. I work in heavy industry and deal with a lot of complicated equipment/ machinery, but I'll be the first to point out that the human beings I deal with are infinitely more complicated than any piece of equipment.
But I would argue that a history teach only needs to know a pretty general, rarely changing set of things. . . It doesn't involve dynamic problem solving and in depth analyzation of complex material
I figured that the conversation was talking about primary education (K-12).
Sure history sounds pretty straight forward, but getting a bunch of children to care about history and actually retain the information is an entirely different set of skills. I love reading about history, but I don't have to teach it.
Everything about education, if it's done correctly, is dynamic. People are dynamic, I think you're really thinking about school in a very one dimensional way.