[pptr]

All libraries you would need are already in Google's monorepo. There is no need for a package manager.

There are a few external libraries in the monorepo. Maybe it's a trickier task to add those. Most Googlers don't need to do that, though.

[constantcrying]

Mono repos don't make it so that suddenly you don't have to manage dependencies for a project. They certainly don't fix CMake.