Actually, it's not the code that directs us, it's the funding. Work in a department that earns its budget annually or are on a project funded upfront? Then no number of scrum masters, backlogs or showcases will see you evolve from waterfall. Likewise if you are funded incrementally per feature set then your team will gravitate towards leaner methodologies. Software manifestos need to be complemented with finance ones for any methodology to have their intended impact.

I felt I was getting pretentious there... maybe I should extend that idea out, something like McLuhan's The Medium is the Message.