spliff, this is an interesting discussion as long as we keep it within a reasonable tone.
I agree with you for the most part. For one, a top MBA will not make you an MD nor a CEO. Plenty of people go to top business schools and are not CEOs; it could be because of either a lack of leadership skills, which is indeed harder to be taught on paper, or different priorities, one for a more balanced life for instance. I would also like to add, as many time pointed out, that many successful leaders did not have a top b-school degrees (eg Bill Gates(given that he nonetheless was accepted at Harvard undergrad though), Sam Walton and many others). Thus, a top MBA is not a sine qua none for success.
Nonetheless, as harsh as it might sound, we have to admit that there is indeed a difference b/w a Harvard MBA and a less known local MBA. The realities of a top MBA are manifolds: (1) The drop out rates is pretty low given the students' dedication to higher education as demonstrated by higher GMAT scores, GPA scores and better work experience (2) Better networking opportunities given the large network of successful alumni who are more than likely to help fellow students. (3) Better networking opportunities also because your flatmate, classmate might very well be the next CEO who will help you out later on in your career. Remember that later career jobs are usually obtained through the social network rather than any type of head hunter (4) Better brand recognition from top tier firms who will offer better career advancement, which is definitely tied with reason #2
Furthermore, there is no point in attending a top B-school just for the sake of it. If you are already having a great job and simply need an MBA for career advancement, then doing a more reputed MBA, an study in an unreasonable fashion for the GMAT, might be a waste of time (and bad for your baldness). That is why people have to weigh the pros and cons and hence the overall intention, I believe, of your message.
Thus, although I do see your point about not being reasonable to overdo the GMAT or about having an unreasonable debt of 100k after graduation, I do have to make a distinction between a top mba, and why people seek such a degree, and a local less known mba.