It isn't so much that he fails at scale as it is that at this point, the majority of effort that goes into any big game is in the content/art and not in the cod

It isn't so much that he fails at scale as it is that at this point, the majority of effort that goes into any big game is in the content/art and not in the code. The reason he can't say "let's rewrite this from scratch" anymore is partly because of the size/complexity of the code, but a lot more because he can't make any sudden changes that will cause the artists to have to restructure their existing work significantly... that's where the scale failure occurs.