Microsoft CEO made a prediction in a keynote in France
that 5 years from now we will mostly be interacting with intelligent Agents instead of Apps.
The GUI of Apps is already interacting with APIs, both internal and external.
APIs could are structured in such a way that GUI could be replaced with other ways of communication, including speech and UI dynamically generated based on API "metadata"
Satya Nadella : Empowering every person and every organization to do more | Innovation et Tech, quel sera votre métier demain ? | Channel 9
this inspired presentation is ended with this quote:
To accomplish great things, we must not only act, but also dream; not only plan, but also believe. - Anatole France at BrainyQuote