[JohnFen]

Honestly, maybe you don't.

But, as a serial entrepreneur for more decades than I like to think about, I can confidently say that there is one thing that you really do need: you need access to people experienced in business, preferable a similar sort of business to yours. You need their advice.

YC can provide that, and has paved the path for it. You can also get it through many other avenues. But whether through YC or not, your business will be more likely to succeed if you can learn from what other people have already done.