Revolutions take two forms. The most familiar kind is the noisy, conspicuous, disjunctive event that marks a clean break from the past. Yesterday, George III was our monarch. Today, he's not. The other kind of revolution is a more gradual and subtle event, when multiple forces pointing in the same direction push people into a new world. The shock of Pearl Harbor, the power vacuum left by a devastated Europe and Japan, a reinvigorated economy, and an aggressive superpower adversary made Americans feel, for the first time, that they needed to be far more deeply involved in international affairs than ever before. Without any formal declaration, Americans became internationalists after 1945.
Something like that second kind of revolution has happened with software requirements. Over the past decade or so, organizations grew increasingly worried about the problems that took root in bad requirements. The problems took many forms (portfolios filled with applications no one was using, users unhappy with the software that complicated their lives more than helped them, ideas that no one vetted carefully, etc.) and arose from just as many sources.
All of these discontents pointed in a common direction: Take requirements more seriously. In Forrester's Q1 2011 Application Development And Delivery Organization Structure Online Survey, "improvements of requirements" appeared at the top of the list of initiatives that would improve software development the most.