Yeah it sounded like Kent just discovered Jevons' paradox and decided to shoehorn it into the article. Nothing here became cheaper, and if by cheaper he means that paying a programmer was more expensive than paying for an AI, even that's not necessarily true once you account for re-work and a host of other things.

If we're going to go with economic/strategy models, I think the Laffer Curve is more relevant. Seriously extrapolating here: AI is optimal for many tasks which if used in those contexts can maximize productivity. Over-using it on unsuitable tasks destroys productivity.