Symbian^3 phones (sort of) already have this, in that you can connect USB/Bluetooth mice/keyboard and attach it to a monitor using the HDMI port. Nokia just haven't packaged it together in a all in one, single connection product like this laptop dock. But the fact that so many phones are getting HDMI out sort of suggests that the manufacturers see them as being portable computers that you plug the extra dumb peripherals into.

I'd say it was more of a "stopping any other software distribution method" decision than a design decision.

Was the hardware ever anything special? The original came out a year and a half after the Nokia N80 that included a higher res camera, 3G, video, etc. Add in GPS, which various phones did before the the original iPhone was released, and the iPhone 3G spec sheet is still lower. Perhaps Apple (correctly) believed that the touch screen UI was enough of a selling point, and decided to have inferior hardware in order to allow them to make large leaps forward every 12 months. What's the bets on a big deal being made of the iPhone v3 having a better camera with video recording in summer 2009?