The point is that I don't think it is the issue of "better written" or "more imaginative" is the issue, but rather more understandable to the mainstream public at large. Consider that The Yiddish Policeman's Union by Michael Chabon or The Golden Compass by Philip Pullman have sold very well within the mainstream market. For the most part, people will understand the premise of books like The Two Georges or Fatherland better, mainly because the "low-butterfly" events help audiences get a better grasp of what is going on. This isn't necessarily always the case (e.g. Resistance: Fall of Man video game), but it helps an audience to accept a story more easily than to drop them into a situation that is completely foreign to them. This is one of the reasons the "same item, different names" strategy of story telling works effectively...With the examples given, I'm not sure which is supposed to be butterfly conscious "hard" AH and low butterfly "soft" AH. I have only read For Want of a Nail, but based on the blurbs for Tranquility Alternative on Amazon.com, it seems both books ignore butterflies at times and consider them on other situations. I'm probably not a good example of your main point, since I have read FWOAN several times and had not even heard of TA or it's author before today. From what I can tell TA is more of mainstream SF/technothriller set in an alternate space age for literary or story-telling purposes. In terms of mass market fiction, AH is still perceived as minor sub-genre of the wider SF/Fantasy genre, which itself is still a niche market - it stands to reason that books which are marketed to appeal to a broader segment of the public (Fatherland, for example) or a few Turtledove books (Guns of the South or The Two Georges) sold better than other better written or more imaginative AH.