At this point, it bears repeating that a major reason why Apple was able to leapfrog others in 2007 with the original iPhone, was not because they invented anything new, but because they had no legacy app code or small displays to support.
Now, five years later, Apple is in a similar boat. They have to tread more carefully in order not to upset current users.
I do believe that Apple has no choice but to start pushing developers in the direction of resolution independent apps, though.
-- As for the competition:
Microsoft was the first to realize they had to cut loose their legacy users, and they created Windows Phone to totally replace Windows Mobile.
RIM did not cut loose from all their old paradigms (I'm not sure they could at the time, even if they wanted to), and they're hurting. Perhaps their coming OS change will help.
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It makes you wonder if the best idea is simply to say "Hey, each device type is good for a five year lifetime. After that, we're going to have to leap forward again. Deal with it."