Nice post Martin, interesting information. I think several of the comments on the Macrumours article touched on some of the reasons behind lower sales in comparisson to iOS, one of the main ones being the smaller user base in comparrison to iOS or PC markets. Another good point was about how people treat downloading content for their home/desktop system in comparisson to an iOS device - they seem to be more cautious when choosing what to download/install at home than on a mobile device.
I agree with what you said about price, lowering it at the peak of your sales probably wouldn't have had much of an effect, not to meantion that a race-to-zero on the Mac App Store would probably be very bad for the market.
Thanks for being so open about your numbers, it's very useful to see this kind of data