My own anecdote. If I'm lying in bed and I want to check a webpage, twitter, email or even ssh to check something on a server...

... and the choice is between picking up my iPhone, or moving a metre to the desk -- I'll just grab my iPhone.

Not to disagree with your point more generally, but I think the iPhone is operating in a sweet spot -- i.e. not the be-all-end-all, but good enough for a lot of daily tasks.