I don't really know if there is much to analyze. The guy went to Stanford and had the priviledge to meet other great folks with the same passion. His connections and this environment is what made him successful.
I'm not selling you an excuse. I'm just saying this certainly played a big part of why he became successful. Stanford has a solid track record for successful start-ups.
In my opinion, applying to YC and hoping to get in versus having staff members on university campus with connections to students who now operate prestigious tech companies and being able to walk the same path they have are 2 entirely different experiences.
Thousands of people attend Stanford, yet not all of those attendees are successful to this level. Also, not all really successful people attend to top universities (eg. this was measured for Nobel prizes). So you need to start looking at other factors too.
You're missing the whole point. Anyone has an entree into the startup scene if you work and follow up. It was a sequence of success and increasing access, not randomly granted, monolithic privilege.
The process begins with opening the level editor in Doom II.