One: because people will pay more per terahash while the difficulty is low. That's kind of obvious: your potential return is a lot higher per terahash while the difficulty is low, so therefore AM can charge a lot more. That effect is quickly subsiding, as evidenced by AM's prices.
I don't see the relevance of price per terahash. When difficulty will rise, terahash per units will rise too, next generation chips will be more powerfull for probably roughly similar price. Income then can remain similar even when difficulty rise.
Two: there is no serious competition yet. Beyond the organic competition anticipated from Avalon, BFL, KncMiner etc getting their shit together, at this point the sales volume of miners is large enough for an established mid-size electronics manufacturer to mosey on over here and embarrass AM price-wise.
Yes, there is no competition. And it will remains like this for at least few months. People know this and this is reflected in the price. When competition will come serious, AM will have a large head-on, reflected in the price too.
Three: electricity cost. Believe it or not, the location of AM (Guangdong province, China) is not the cheapest place for electricity. Don't quote this figure, but I believe it comes out to about $0.06/kWh. As competition ramps up, money getting in on a piece of that 26% APR will launch huge farms in places like Washington state or Siberia where the price is $0.01/kWh - and they will do so by licensing the BitFury chip, for example, not by buying expensive AM hardware. AM will have trouble competing.
AM has already revealed plans to legally move away from China, with their actual financial power, I don't think they couldn't move server farms away, wherever they will be happy with electricity costs, climate and regulations.
I've sold all my shares.
This makes you sound just as biased as the other people in the case you mentioned:
Anyone saying otherwise has ulterior motives (they probably still own a lot of stock).