Have you ever experimented with an opposing strategy? (Funding "non-technical" founders with "weak" personalities.)
Probably not, lest you would risk your reputation. Hence, you might not have evidence to show that this approach would not yield suffcient numbers of "big winners" to justify the investments. For example, if someone sugested the hypothesis that from a set of a given size of non-technical founders with weak personalities, some "big winners" will emerge, could you disprove that? If you wanted to be scientific, you would have to test it, repeatedly.
From my intepretation, I think one of the points in the pg essay is that human "intuition" will only take you so far toward the "big rewards". By its very nature it steers us away from the counterintuitive and protects us from taking what others would perceive as unreasonable risks. It will stop you from adopting a strategy that no one else is using that might get you labelled as foolish (but, as history shows us time and again, might actually yield an enormous reward).
In hindsight we'll continue to see that some of the biggest winners would have been viewed as unreasonable risks by many VC. Foresight won't allow us that vision. So-called intuition will stop you from investing in a "big winner". Hard to accept, but true.
It might not yield any "big winners" (then again it might) but it would in either case produce evidence that we could use to try to disprove certain theories.
"highly profitable or highly entertaning to watch..."
or highly informative
Does this also mean that the "big winners" will not come merely from a pool of what appear to be bad ideas, but from a subset of that pool: bad ideas put forth by founders the VC thinks are impressive? That too, seems somewhat obvious.
Taking it one step further, can you separate the "idea" from the "founder" in assessing the project's chances of being a "big winner"?
Maybe that was the goal of requesting that people should apply to YC even if they had no "idea".
After all, the supply of "bad ideas" is potentially limitless.