Otherwise, the qualifiers that apply to any other startup in general, apply.
you dont have to get into YC to succeed, but understand he was talking at an exclusive event - the final YC dinner.
Also understand the odds. He picks teams most likely to succeed. If he rates odds of success as 1/2 (or whatever the article said), and the odds of getting in are 20/400, then the odds of success for you and me, those who didnt get in, is 1/40. Which is 2.5% and vibes with I recall that people generally say that startup odds are 2%.