The things I have heard him talk about, I can't imagine a YC company doing that. Not saying that they won't, and going forward that may be the case, but I can't recall ever hearing many/any YC company making synthetic beef, or new types of seed, or other stuff that I hear Vinod talking about all the time.
Now don't get me wrong, I am not saying that there are no YC companies that do these things. It's just that based on what I know, if there are any, it is a small subset.
From there, then it is about whether or not the company founders and Khosla Ventures work well together and see the big picture similarly. Not every company that is in an industry you invest in, will be suitable for you to invest in - for a variety of reasons.
So, if we were to be generous, I would say 5% of all YC companies would make up the total "investable pool" for Khosla Ventures. That's only 20 companies. From there....there is no telling why they haven't invested - e.g. all 20 could conflict with existing portfolio companies, or maybe only 15 do and the other 5 are not as impressive as they would like or any other reasons that disqualify them from being investable and reaching a deal with Khosla.
So all in all....if YC were producing 400 of the types of companies that fit Khosla's thesis...then I would agree with you.
But that is clearly not the case....so I don't think that is a useful data point.