I've definitely seen it happen in SF.

I've personally been part of hiring at least four dev boot campers. All were green but you could tell they fundamentally understood logic and would eventually figure out the stack given enough mentorship. They all turned out to be great jr hires.

Most previously had compelling careers in other fields before switching. I can remember a lawyer. And one worked for the CIA?

Natasha Murashev was one of them. I see her travelling the world, speaking, and has a large dev following on Twitter. https://twitter.com/natashatherobot