They're saying that you'll have to switch from ChromeOS to GoogleOS to keep getting updates for the full 10 years.
"All Chromebook platforms will get regular automatic updates for 10 years"
Are they going to make the switch automatic? It sure doesn't sound like the sort of transition that can be done automatically.
That's why this branding decision is a mess: Googlebooks are meant to be a good Gemini experience, and probably have some minimum requirements for local inference. The OS for these machines is all one probably very messy derivative of the same code base, where an android runtime is centrally important to having apps on that platform. But now the imperative is to center the AI experience, whether or not branding and product formulation can be made understandable.