A disruptive innovation brings an evident solution to a key unsolved question. And a truly disruptive innovation does the same for a key unsolved question that had never been asked before.
Simplicity often comes with a paradigm shift, a total reformulation of the initial question, a complete change of plane ; you have to think out of the box, where old problems offer new solutions, where old constraints open new horizons...
A disruptive innovation changes the very way we consider our environment.
(answer to the question "What does disruptive innovation mean to you?")