With companies spending more than ever on artificial intelligence, they are also tracking how employees use AI in unprecedented detail. Yet many CEOs hope, but still can't tell, if it's making workers more productive .  More than two-thirds of enterprises still rely on estimates, like time saved or projected cost reductions, rather than measured financial results to assess AI's return on investment, according to a 2026 survey of 100 senior AI enterprise leaders from ModelOp, an AI lifecycle management and governance platform. ModelOp refers to the gap between AI activity and measurable return on investment as the "AI value illusion."  "Almost every Fortune 500 is tracking overall AI usage," said Jim Olson, CTO of ModelOp.…