The first program you build in Noogler training takes more compute and io to build than the Linux kernel. The distributed build systems laughs at such a trivial program and barely breaks a sweat at programs 10x that size.
Google has a giant monorepo. It is too big for git. (Virtually) everything is built from source. Building a binary that just runs InitGoogle() is going to crush a laptop.
I believe that there are also a bunch of IP reasons for this policy, but from a practical perspective doing everything with citc and blaze is really the only option.