> Free markets are generally good at determining value, and for decades the market for young business leaders has given a strong vote of confidence to the graduates of top MBA programmes.

The opposition's entire argument hinges on this one sentence, but they supply no evidence to refute the idea that this segment doesn't behave like a free market at all. As the moderator pointed out, there's no reason to believe that this is anything other than the effect of the "old boys' network".

The opposition needs to come at this from another angle - to show that an MBA gives advantage to the holder in such a way that it isn't clearly an effect of networking rather than learning. Unless they can do that, I will remain unconvinced. I will, however, admit that this a big ask. Performance of business leaders is difficult to measure in a meaningful way.