Interesting approach, but funny that he never mentions the single key word that makes it all possible: revenue. Whether you're bootstrapping or not, the best way to verify your concept AND position yourself to run a marathon is to FIND A CUSTOMER. Putting a team together, launching, getting into yc, taking serious investment - these are all great milestones. But there's still nothing quite like depositing a customer's non-refundable vote into your bank account. That's the day your world REALLY changes.