Many employees put decades of blood, sweat, and tears into climbing the corporate career ladder—but the top rung is missing the “forgotten generation” of workers, and it may be knocked out from their AI hesitation.

About 41.5% of CEOs in the Russell 3000 are at least 60 years old, part of the baby boomer generation, up from 35.1% in 2017, according to research by the Conference Board and Esgauge. Meanwhile, the number of millennial chief executives, in their 30s and 40s, has increased from 13.8% to 15.1% over those eight years.

But Gen Xers, entering the senior-level stages of their careers, aren’t seeing that same rise in representation. About 43.4% of CEOs are in their 50s—a fall from 51.1% during that same period.

While Gen X still represents the greatest proportion of CEOs, they face dwindling opportunities compared to their millennial counterparts. Instead of giving their jobs to the next generation below them, baby boomers are skipping over Gen X in favor of promoting younger talent into their spots.

Much of this change can be linked back to AI’s rising prominence in the workplace, experts say. Nearly all companies are integrating the advanced tech into their business strategies, and millennials by and large have the digital skills to lead that change.