More to your point, he didn't hire extras to port over to Clojure, in fact he fired most of the previous team and replaced them with 4 developers. So his point

More to your point, he didn't hire extras to port over to Clojure, in fact he fired most of the previous team and replaced them with 4 developers. So his point was that he gained BOTH developer productivity and server costs by doing the move, which improved the cash flow.