Well, riddle me this Batman: Why would a highly paid analyst at a securities firm, who provides research to the firm and its wealthy clients, give it out to the great unwashed, gratis? Is he just that nice a guy?
There are more than just iPads and iPhones in the world? He figures that if he correctly predicts popular things like this, then maybe people will think he's smarter than the average analyst and use him for their actual investments. And it gets his name and firm out there to the masses.
Would you have heard of him if he didn't make iDevice predictions? No? Didn't think so.