Realistically, I don't think you can have a minimalist, clean and focused code base with thousands of engineers pounding away at the keyboard. You ought to make some trade offs with that many employees.
Google's operations probably require X lines of clean code added everyday by 10% of the engineers (so ~5000 instead of ~50,000 engineers), but because of the sheer number of engineers Google has, that are supposed to do something continuously to show performance, Google has ended up with ~10 or ~100 X lines of daily bloat accumulation.
Sounds like a textbook example of too-many-hands-spoiling-the-broth.
