There are some wins from AI now but it’s kind of telling how companies like Microsoft have to trick customers into paying for it with changes to their plans because there just aren’t enough people seeing real value to the point where they’re jumping to pay more for it.
How do you measure developer productivity? Code quality? Developer happiness? As far as I know, no one in the industry can put concrete numbers to these things. This makes it basically impossible to answer the question you pose.
There are of course many factors at play here, and a substantial percentage of CEOs report a positive RoI, but the fact that a majority don't shouldn't be dismissed on the basis of this being difficult to measure.
Or the fact we are woefully unprepared for a peer conflict. We wasted how many trillions in the middle east? We cancelled how many modernization programs to fund counter insurgency programs instead?