I think the author is missing part of the point. YCombinator is simply a way to make something that's very very hard to do just that much easier. Nobody should bank everything on getting accepted (I know I'm not). Just because you shouldn't bank on something doesn't mean it's not a valuable thing.

The author is right in that you should plan on doing it without YC help. My point is that you should still try to get YC's help. It'll be worth it.