Karl Popper observed that if you had a reliable way of forecasting future technological change, you'd probably be able to just make the future technology, so people who prognosticate about this kind of thing are really just guessing.
In that vein, Horace Dediu tweeted a link to this 2008 report on the smartphone market from RBC's analysts, which includes the above projection. They managed to underestimate Apple's likely success to a degree that would be amazing if not for the fact that they were much more dramatically wrong about Android. Everything else is totally wrong. Nokia doesn't even make Symbian phones anymore.
Some of this is just normal straight-line projections—people hesitated to say Android could go from zero to market share leader in a matter of years—but Page 21 offers a fundamentally wrongheaded look at the underlying technology. They segment the market into a "media-centric" market (depicted by a hip lady wearing red) and a "productivity-centric" market (illustrated by a dude in a suit with a white shirt) and forecast that the availability of a QWERTY keyboard and a removable battery will be key features for the productivity-centric segment. It's only a "media-centric" person, they thought, who'd prefer a bigger screen and a slimmer profile to the basic BlackBerry form factor.
So, of course, if you think that the overall market for large-format touchscreen phones will be limited to a particular market segment ("teenager/student, gadget fan, music/TV/movie junkie, trendy consumers") as opposed to normal people going about their normal business, you're going to end up hugely underestimating Android and iOS.