I remember Jobs talking about never making a larger phone. I really wonder if it was a case of him caring about "taste" over "giving people what they want." There was some leaked Apple internal document where they said that people wanted larger phones. The post-Jobs Apple created larger phones to meet market demands. One thing that always makes me giggle, though, is the fact that if you double tap the home button the…
The thing is, at this end of the technology lifecycle there are always tradeoffs to be made. For me, the 4" (and to a smaller event the 4.7") devices sacrifice too much in the way of screen size, battery life, and keyboard usability. In exchange for those things, I sacrificed one-handed use for some use cases.
There's a lot more to 'user experience' than just the # of hands I need to send a text message... And it turns out that with my watch I do about 70% of my messaging (by far my most common 'quick one-handed' use case) with my phone in my pocket anyway.