I've expressed this theory multiple times on this board, not so much prehistoric times, but just going as far back to 100 or so years ago, it seems like Aspergers tendancies wouldn't be a huge concern. And if you could put yourself to use with your Aspergers special interests and do cool stuff, even better. But, the things we concern ourselves with on this board socially, things like dating, high school, etc, were nonexistent. Marriages were arranged back then, so any social difficulties you had with women were pretty irrelevant.
I can go on and on with my conjecturer, but I'd just like to speak of my personal experience. In my personal experience, when my power went out, I just LOVED it. I was really calm, rationally, and reasonably prepared for such an event. I loved it, because it was like having the tables turn on the world for once. During the week with no power, when I was cooking things on my grill and car exhaust manifold, taking showers at the gym, I simply loved it. To me, it was so easy to "figure" everything out, all I had to do was make sure food was prepared, that's it. No multitasking 800 things, I loved it. That week, I only had one cup of coffee in the morning everyday. Now, it's back to "as normal" and I need like 3 energy drinks a day to keep up with everyone else.
So my theory, the reason why Aspergers became a diagnosis was because as life went on, the "NT" became more advantageous due to the change from societal standing being more based upon your abilities in what you could "do" vs how you make people "feel." It's happened in USA with just jobs alone, at the turn of the century most low end jobs in America were factory jobs. Now, most low end jobs in America are customer service jobs. So to me, I simply think of Aspergers/HFA/etc as just being a person that's an anachronism in this Brave New World.