In a blunt companywide memo last year, Micha Kaufman, the CEO of freelance marketplace Fiverr, had some harsh truths to share with his employees.

“AI is coming for your jobs. Heck, it’s coming for my job, too. This is a wake-up call,” he warned. A year on, he has a message for the C-suite trying to ride out the AI tsunami.

“Don’t be a cheerleader. If you’re not practicing, don’t preach,” Kaufman tells Fortune. “You can’t make AI a value on the wall and then not behave by it.” CEOs are currently treating AI as a training problem, he says—­buying products, ­running a seminar, and checking a box—when the real challenge is a cultural one that starts at the top.

Across industries, there’s palpable angst about the impending AI onslaught and how best to prepare workers, managers, and—above all—themselves for the new reality that lies ahead. The technology is moving faster than any organizational playbook can keep up with, and the executives tasked with leading the transition are often figuring it out in real time. What’s more, many are seeing a gap between their companies’ AI ambitions and the results. There are lots of pilots and hype—but only a small number of organizations, usually in tech, are seeing transformative gains.