I'm thinking he wanted a new form factor to show that IT'S NOT AN IPHONE4. We're getting into the realm of tail fin marketing.
That way, when people are on their 2 year contract cycles, you either sit on the "new shiny" or the "advanced shiny" cycle, so consumers rarely lose out depending which cycle their contract ends in, since there are pros and cons for both.
I'd say its smart business.
It's not like we're launching new networks every year or two, or individual ARM cores are going to make huge leaps in performance.
Have we trained everyone to worship the new/shiny when we're probably hitting a short-term asymptote?