I think this goes to the problem:

Like any strategy, if you fail to stick to the plan, your chances of success decrease: if you’re trying to lose weight, and you stop keeping track of calories in and calories out after the first week, guess what? The only way you’re going to continue to lose weight after that point is by pure dumb luck.

I completely agree, of course. If you don’t follow your strategy, it can’t deliver on its promises. The thing I’m grappling with is that maybe the plan really can’t be stuck to. It seems pretty well proven that waterfall can’t work for this reason. It’s just too hard to do right. I’m feeling the same about agile. As simple and obvious as a methodology it seems, and as straightforward the rewards seem to be, I can’t seem to find any team that is really, truly following scrum over the long run.

I’m just one guy in Manhattan so my experience is obviously limited. I may just be having bad luck :).