You can argue the reasons all you want, but the fact of the matter is that the article in the OP draws nothing but non sequitur conclusions. Games on mobile devices are generally far simpler and easier to develop than games on consoles, so of course a majority are planning to develop for that medium. Similarly, my understanding is that it's easier to develop for PC than it is for consoles since it's all fairly standardized.
The only thing this article proves is that developers tend to put their efforts into areas that require less of an investment. Go figure. In addition, this survey seems to be aimed at a wide variety of developers. If they'd focused just on the major players, I might pay more attention, but a guy who develops a tic tac toe game in his basement wasn't exactly going to be thinking of developing an Xbox game anyway.