The new Plus category of Chromebooks is an assurance that you'll get a higher level of performance and features but still at a reasonable starting price.
With Chromebook Plus, you're guaranteed to get at least the following specs, with a starting price of $399:
- 12th-gen Intel Core i3 or AMD Ryzen 3 7000 processor or better
- 8GB or more of memory
- 128GB or more of storage
- 1080p-resolution IPS LCD or better
- 1080p webcam with temporal noise reduction
Yup. My point is simply that with the latest announced support cycle ChromeOS has a longer support cycle than any single Linux distro LTS release I know of, and even when out of support a Chromebook isn't automatically an ewaste paperweight.
But you're comparing apples and oranges. With a Chromebook, the OS is being updated to a new version every month. You're comparing a device being able to support a certain number of versions of an OS to an OS receiving application and security updates. It's a meaningless comparison because a typical laptop running Linux can be upgraded to an arbitrary number of new versions of any Linux distribution.