The day the business can no longer make money by spending money, the project has failed. It's impossible to have a conversation over software of uncertain quality. The cost of making changes rapidly rises, and the conversation falls apart. Painful Paradigm Shifts Thomas Kuhn's The Structure of Scientific Revolutions suggests that paradigm shifts are always painful. Few people move from the old paradigm to the new.
Newcomers adopt the new paradigm, while adherents to the old paradigm disappear.
Fixed-scope contracts and other noisy ghosts of the manufacturing floor will be with us for at least a decade. However, a new generation of business leaders will seize on the opportunities inherent in conversational development. They'll learn to treat programmers as neither priests nor drudges, but as equal partners in a conversation about business. These leaders will first apply this knowledge to the hottest business opportunities. Gradually, developers will embrace conversation as the best way of doing things.