Agreed. For handsets, it looks like it's cooking down to iOS, Android, RIM (ultimately strictly corporate, then fading away if they can't stay in front for value added... using the iOS email interface, all I can say about it is if mail were my bread and butter, anything would be an improvement, and this is allegedly RIM's strong point), and Microsoft's various half-assed attempts to buy Windows Whatever into the marketplace.
For my money, I think the "now" will get More So over the next couple of years - businesses under contract will stick with RIM, nerds will use Android,hipsters will use iOS, people who've never bought a mobile phone might get suckered into whatever Microsoft is trying to push.
In a moderate span of time, RIM will be absorbed by Google or Microsoft - by GOOG as a business grab or by MS as a desperate marketshare grab. The marketplace will then consolidate to iOS, Android, and whatever Microsoft thinks they can offer, with RIM integration grafted into Android or Microsoft offerings. (Apple will continue to put more effort into their website's description of iOS's mail capabilities than they will iOS's actual mail capabilities, as they always have)
Phone OSsen will ultimately boil down to iOS, Android (merging with ChromeOS as developers continue to think the iPad is something worth targeting) and possible Windows-Whatever, which may have an actual strong advantage given the sudden realization that despite years and years of hardware and software development in the slate/tablet form-factor space, the tablet PC did not exist AT ALL until Apple invented the iPad. Never mind that you can run photoshop "out of the box" on a PC tablet running Windows - Apple has nuked the hell out of marketing in the "tablet space" and despite being massive orders of magnitude more capable, everyone else is now playing catchup, thanks to massive marketing fail.
Diatribe divergence aside.... five to ten years from now? Apple, Google, Microsoft, RIM. In alphabetical order, specialized, and fighting for dominance as opposed to swimming in moneyhats. Apple as the new Sony, Google as the new Amiga, Microsoft as the new IBM, RIM as the new-old IBM, relative to the market-space.
Yeah? No?
Who knows. There's plenty of time for another company to rise up and turn the industry on its ear. Smartphones are roughly where PCs were at in the early 80s - something might just come along and make iOS look like CP/M.
I wouldn't bet on it, but I wouldn't count it out, either.