I know or have met a ton of ex-Googlers, only a few ended up on the startup path. Any workplace can get old after a while for all kinds of reasons. Or perhaps

I know or have met a ton of ex-Googlers, only a few ended up on the startup path. Any workplace can get old after a while for all kinds of reasons. Or perhaps they just couldn't figure out how to navigate the internal politics to end up on teams doing world-changing stuff (let's be honest, the vast majority of engineering going on at google is pretty boring maintenance and bug fixing like anywhere else).