And applying for an entry-level development position. He is not lacking in hubris, so imagine the managerial nightmare he'd likely impose for a collection of non-managers.

I've checked his CV in LinkedIn and he certainly has an interesting CV, but not necessarily a strong one for a software engineer in a big company.

I have no idea about how recruiters select profiles in Google, but maybe having an strong background as entrepreneur is a red flag ("he'll leave the company for his own project!"); or maybe the lack of bachelor degree... (or maybe pure ageism)

I can't say I agree, clearly spending that much time shows a lot of passion, but Google tends to have pretty harsh and silly selection process, where a silly small thing or mistake gets you rejected.