wired has a feature on scenario planning which provides a glimpse into the world of planning. it's a good quick intro by example where we witness the planning of an aerospace engineer's career, I think I would have added an 'improve this scenario' section at the end.
People criticize basic scenario planning because the plan usually lacks either scenario comparison ( show that A is strictly more likely than B ) or assumption omission ( just didn't think of it ). Both provide great starting points for exploring: with comparison, we have to transition from a thought experiment model to a numeric model of the processes at work (although that macro would probably lose readers at the 2-n rate where n = number of equations); with omission, we can look at data like the expected supply and demand of aerospace engineers relative to other disciplines (what happens when another major industry opens up? would you want to advantage of that opportunity and change careers?).
Scenario planning seems sometimes like a modern-ish religion, not too far from its entrail-gazing past. We see the same cults of personality and legitimization tactics that we have seen for several millenia. We haven't yet seen a McDonald's-level scale-out (unless you count end-user financial planning ;).