Simplicity and sophistication of the UI/UX has nothing to do with the simplicity of the overall system. Underlying system is probably more complex because the UI/UX is simpler.

So maybe Gruber should have said that UI is simpler, but not the iPhone. If iPhone is so simple, why aren't other big companies as successful at creating new phones? Clearly, things are not as simple as some people would make you believe.

Also, a jump from Razr or Palm (for example) to iPhone is much bigger than that of iPhone 1.0 to 3.0.

Had Apple released a Razor-like iPhone and then iterated to iPhone 1.0 system over a year or two, I'd buy Gruber's argument. But iPhone was clearly 'from the future' when Apple presented it and everyone else was scrambling to catch up. So Gruber's argument is not really serious.