That's crazy that you didn't get the job. Considering AirBNB's growth rate, it seems they could have taken a risk that someone like yourself would grow into the position.
If Feynman were still alive and wanted to work as a programmer at your startup, it'd be foolish to turn him away. This was a guy who went from "zero knowledge of how a space shuttle works" to "knows the design of the Challenger shuttle in detail, and is able to spot overlooked problems" within a couple weeks. So he'd certainly have no trouble reaching rockstar programmer status at your startup within a couple months.
But I'm getting the feeling most startups would turn him down if he wasn't already a rockstar programmer the day his interview rolls around. That seems a little nutty.