Jim Dunnigan:
As early as 1972, we had hints that SF and fantasy would sell better than historical games. Remember, this was several years before D&D came along. In 1974, we published Starforce (after it got very high feedback ratings.) Redmond Simonsen, despite his intense interest in military history, was a big SF fan, so I had no trouble getting him to take the lead in doing our first SF game. Starforce outsold the average historical game by by more than 3-1. All SF/fantasy games out sold historical games. There was no SF competition out there for Starforce, which helped. But it was obvious that from that point on SPI would have to publish a lot of SF/fantasy titles to stay in business.
Note also that all the historical games on that top 11 are simple (to play) ones.
So, it's up to AGEOD to decide what is History

It may be a step (back AGE to the root?) to learn the engine (and have experience in this system) for future History game consummers, as AGE games seem becoming more and more complex.