I find this very similar to the early PC days. Back in the day, you had Apple and Amiga competing in the consumer market and Microsoft/IBM was around, but was basically confined to the enterprise world. The perception was that MS/IBM was for business. If you wanted a computer in your home you bought an Apple or Amiga device.
If you had looked at the three, you'd have thought Amiga was going to be the clear winner. It was cheaper, actually did faux multi-tasking and supported some 3D rendering stuff. It was a better product than Apple or the IBM clones in many, many ways. Any observer would've been likely to predict that the MS/IBM clones would've been stuck in the enterprise world where they were useful and that Apple and Amiga would eventually end up splitting the consumer world in some way likely with Amiga on top.
All that being said, I think in 5 years RIM will be dead. They'll either go out of business or they'll be gobbled up by some other company wanting their patents more than anything and their products will go the way Palm did. I think Android will end up where MS is in the desktop world although not with the 95% market share that MS enjoys. You'll see Android on everything from high performance gaming devices to cheap, crappy things you hand your two year old to play with. WP7 and it's variants will end up on mid to upper level devices. MS will so integrate the phone platform into Windows and XBox (which will end up as a set top box that is also a great gaming system in 5 years) that many people will adopt it. Apple will fall to 10-15% just because it's only one device being sold by only one company and other devices out there will be just as good or better or better integrated. Apple will continue to rake in more money from it's third place position than MS, Google or any Android handset maker does.