That only works for a selected set of chromebook. And you still have an end of life date that is fixed.

My girl friend's school is having to dispose of about 300 chromebooks for precisely this reason. Most are still functional, but now unsupported. They would be totally usable if they weren't being deliberately binned by Google.

This is an environmental crime, as is a lot of support ending the useful lives of devices. These externalities are created by companies who make huge profits, and don't have to deal with what they have created. I've thought this for years, but part of the problem is that everyone is convinced they need to use windows (they don't), and everyone likes new and shiny.