I think the math behind YC and incubators can sometimes falsely justify an increase in the quantity of companies accepted.

If you look at each class and say, "Well, last year we had 5 breakouts out of 50. Why not increase that denominator to change the numerator?"

Unfortunately when you do this too quickly, the numerator doesn't change. It stays the same or sometimes even decreases (in my example, holds at 5).

Staying focused while growing is a very difficult thing to do.