My guess is that it's an extreme case of Conway's law, with many teams that produce mountains of code hidden behind some API. Not to mention codebases provided

My guess is that it's an extreme case of Conway's law, with many teams that produce mountains of code hidden behind some API. Not to mention codebases provided by external firms, which could amount to a large % of all those KLOC. I'm interested in how they avoid "Roman empire syndrome", as in owning more software than they can maintain while actively expanding it.