It's also because as you increase organisational complexity, you need to manage it somehow, which generally means hiring more people to do that. And then you need to hire people to manage those new managers. Ad infinitum. The increased complexity begets more complexity.

It sort of reminds me of The Collapse of Complex Societies by Joseph Tainter. These companies are their own microcosms of a complex society and I bet we will see mass layoffs in the future, not from AI but from those companies collapsing into a more sustainable state.