I've worked on codebases all the way tens of millions of lines of code. Obviously not in the sense of knowing all the dusty corners of such codebases, but still, I did enough work on them that I had to navigate my way around millions of loc. It's not easy! The problem is that you can't possibly know even a sizeable fraction of such a codebase well. Instead you can know small corners well and know your way around the internal and external interfaces so you can find gotchas and answer questions as you research. The knowledge you build is hard to communicate to others, too, so bringing others up to speed is not easy either. So for me TFA hits all the right notes.
But I've also seen things like the ZFS team at Sun deliver something unbelievably good that started as a skunkworks project that senior management didn't really know about until there was enough to show to justify a large investment. Sun was like DARPA: not micromanaged from the top. Sun failed, of course, but not because of this.