Old habits die hard. You'll notice neither keyboards nor nice have changed fundamentally since their inception, and keyboards were based on what? Typewriters.
It's not that the originals represent the best of all conceivable designs, it's that people are familiar with them and have an expectation that they'll look and function a certain way. Overturning an existing standard requires that the new candidate be so vastly attractive and/or superior that people (and I mean the mainstream, not a few nerds) are willing to re-learn their most basic technology habit- how to interact with their devices. Personally, at this late stage, with nearly every English-speaker alive knowing only QWERTY and more and more focus going into alternate input methods like voice and gesture, I have a lot of doubt that text input will ever move past the keyboard layout we all know.