[Larrikin]

From what I remember from phone history, the original iPhone was the size it was due to extensive research to ensure a Japanese woman's hand could reach all parts of the screen and there was a planned big push into Japan, which mostly succeeded at the time.

But Korean women actually lead the push for bigger phones, since they could keep larger devices like the Samsung Note in their purses and using more than one hand turned out to not be a big deal to most people if it meant being able to see more content/detail on the screen and better battery life.