Not that I don’t believe you, but where do you see this?
The reason it's not transferrable is that Google has its own version of EVERYTHING: version control, an IDE, build tools, JavaScript libraries, templating libraries, etc, etc. The only thing I can think of that we used that wasn't invented at Google was SCSS, and that was a very recent addition. Google didn't even use its own open-source libraries like Angular. None of the technologies were remotely usable outside Google.
It might sound cool to use only in-house stuff, and I understand the arguments about licensing. But it meant that everything was poorly-documented, had bugs and missing features that lingered for years, and it was impossible to find a SME because whoever initially built a technology had moved on to other things and left a mess behind them.
Some people may be able to deal with the excruciating slowness and scattered-ness, and may be OK with working on a teeny slice of the pie in the expectation that years later they'll get to own a bigger slice. But that ain't me so I noped out as soon as my shares vested.
My wife, who grew up in a normal family, thinks the fact that my family's idea of a good time is listening to a cassette of "classical music humor," is the nerdiest thing ever.
I was just listening to the 'WTWP' album yesterday. Thanks, Dr. Schickele, for being such a cherished part of our family!