Google has formally announced that its ten-year support commitment for Chromebooks will end at eight years — or more precisely, that all ChromeOS updates stop in 2034 regardless of when a device was purchased. A Chromebook bought today gets eight years of updates, not the ten Google previously pledged. The shortfall is disclosed in a support document explaining the transition to "Googlebook OS," the Gemini AI-infused successor platform Google is positioning as ChromeOS's replacement. The mechanism is straightforward platform obsolescence. Google launched five consumer-only Googlebook models through hardware partners, none targeting the education or enterprise fleet markets where ChromeOS built its installed base. The support document promises that "many newer commercial Chromebook models will be capable of upgrading to Googlebook OS" — but no migration paths exist yet, no device eligibility list has been published, and existing ChromeOS management licenses will not transfer. Fleet buyers who chose ChromeOS specifically for its low management overhead now face a mandatory re-licensing event on a timeline Google controls. The education sector is the most exposed constituency. Schools adopted Chromebooks en masse precisely because they offered decent hardware at low prices with minimal IT burden and a long support window. That value proposition now has a built-in expiration date two years shorter than advertised, with the replacement requiring new licenses for management tools and carrying an AI stack (Gemini) that schools never asked for. Google frames this as a generous transition. The support document states it is "committed to supporting your transition to Googlebook OS." But commitment without details is marketing, not policy. The migration paths are unspecified. The eligibility criteria are unspecified. The licensing costs are unspecified. What is specified is that the old platform dies in 2034 and the new one bundles Gemini. The practical impact for devices currently deployed is limited — most Chromebooks bought in 2020 or earlier won't still be in active service by 2034. But the signal matters more than the immediate harm. Google has demonstrated that its support commitments are unilaterally revisable, which reprices the risk of any future Google platform promise. Schools and enterprises making five-to-seven-year procurement decisions now know that Google's stated support windows are ceilings, not floors. The deeper play is the AI land grab. Google needs Gemini distribution, and Chromebook's installed base — particularly in education — represents captive eyeballs. Sunsetting ChromeOS two years early while offering a Gemini-bundled replacement with mandatory new licensing is not a support transition; it is a monetization event dressed as a platform upgrade. The absence of education-focused Googlebook hardware at launch suggests Google is sequencing: lock in consumers first, then leverage the support cutoff to push institutional buyers onto the new stack. The twenty-year question is whether platform vendors can unilaterally shorten support commitments with no penalty. If so, stated support periods become marketing claims, not contractual obligations — and the total cost of ownership for any cloud-dependent device becomes fundamentally unpredictable.