Well, I've probably overstated when I referred to "Average Joe", but you know me already - I tend to overreact from time to time

When I sad "Average Joe" I meant "applicant from no-name country, working for no-name company, educated at no-name university". Of course, you are right regarding academic abilities and leadership potential of these people - they are not average at all.
Beleive me, I know couple of "no-name country, no-name company, no-name university" guys from my country (which is, obviously a no-name country

) who made careers abroad (we are talking McKinsey or Lehman overhere), returning home and becomming ministers or deputy prime-ministers. The only stuff they had in their resumes were HBS, Haas or Columbia B-schools. Of course, as you said, they were all natural born leaders and very smart peole, no doubt about that (if they weren't, they wouldn't have entered such excellent schools).
If some "no-name country, no-name company, no-name university" guy graduates from IMD, he will remain just that. Knowing that, IMD admission officers wouldn't have admitted him in the first place. My point is that schools like IMD provide very little (if at all) added value. You have pretty decent chance to leave that school with nothing you already haven't had 10 months earlier.
I have to repeat, I have great respect for anyone admitted (or even just interviewed) to IMD - I have not even the slightest doubt that they are very acomplished and successful. As you noticed, it has its own market corner and schools like this one should exist in the future. I am just confused why it is referred as top school, side by side with LBS and INSEAD.
Schools like Chicago, Wharton or LBS aren't trending younger either, admitting hundreds of 30+ people each year. What I'm trying to say is that less acomplished person will gain much more from attending any of these three schools than IMD, and that is of much more consideration (at least for me) than rankings based on salaries and selectivity.