I don't think much explanation is necessary. YC is never going to catch every potentially successful startup. The process can be refined, but you will never recognize all of them. Averages being what they are, I think YC has done very well. The Codiqa team showed tenacity, and when YC didn't work out for them, they found another route. They are a great example for other startups. None of this should put YC in a negative light.