The AI pundits often seem to apply the logic that code output is directly proportional to revenue and/or profit, and as such it follows that an AI usage increase leads to more code which leads to more revenue.

I don't believe this aligns with the reality of any major company, unless your business is in the literal sense "selling code" your revenue and profit is tangential to the quantity of code you produce. Google is a good example of this: most of their revenue and profit comes from their ad network, which is disconnected from their development productivity and instead heavily reliant on network effects and time in market. If I was a new competitor with infinite AI funds to throw at whatever problem I choose, I can't simply capture their market by developing an exact copy of Google's ad platform. In the same way, Google can't substantially grow their ad network by coding "more" or "better", they still need more customers and consumers to interact with their network to see any increase in revenue.

So it doesn't directly follow that a productivity increase will inherently follow an AI usage increase.