A less original composer merely assimilates. Many bad composers lose most of that which is great in music through simple-minded attempts to be revolutionary. What they get in return is usually a great disappointment. For more detailed thoughts on usurpation in literature I recommend Bloom's Agon . Usurpation is conservative and progressive at the same time, and I find that for the most part, important musical developments would be better characterized as usurpations rather than revolutions.
Usurpation implies knowing intent.
I cannot call this a revolution because, as Schoenberg himself tells us, the revolution took place gradually throughout the 19th century, prior to the refinement of the twelve tone language. Schoenberg delivered the coup de grace, preserving the primacy of the theme and dealing with the consequences. He usurped the role of theme as unifying principle in that he turned some things upside-down in the process of shedding the trappings of the old music. It is a strong usurpation to the extend that it is compelling. It is, as it were, the melody had been generating the structure all along.