No physical keyboard doesn't always mean immediate large-scale writing failure for all people. I think some people either just get used to it for extensive prose, or don't.
In Japan, the keitai-novel - novels written by young authors often entirely using featurephone numpads - has gotten past its initial craze and appears here to stay as an established genre. Even for other genres, there has been a recent example of a self-published science fiction novella scoring high in the just-started Japanese Kindle/Kobo sales rankings, having its majority written on an iPhone.
I imagine the general populace will gradually get accustomed to using a non-physical-keyboard device for extensive text input, especially as more kids emerge experiencing the touchscreen as their first and only input device. (And the aforementioned author wasn't even that young - IIRC he's around 40!)
In Japan, the keitai-novel - novels written by young authors often entirely using featurephone numpads - has gotten past its initial craze and appears here to stay as an established genre. Even for other genres, there has been a recent example of a self-published science fiction novella scoring high in the just-started Japanese Kindle/Kobo sales rankings, having its majority written on an iPhone.
I imagine the general populace will gradually get accustomed to using a non-physical-keyboard device for extensive text input, especially as more kids emerge experiencing the touchscreen as their first and only input device. (And the aforementioned author wasn't even that young - IIRC he's around 40!)