It's the other way around. If you want ChromeOS (in particular with its Verified Boot system for the OS image [1]), you need special hardware that comes with Chromebooks, including the Framework Chromebook. That has nothing to do with the ability to run Linux, though.

If you don't care about Verified Boot, you can install ChromeOS-Flex on a Framework Linux device (https://www.reddit.com/r/framework/comments/um0mk6/chromeos_...)

On the other hand, installing Linux on Chromebook hardware is straightforward.

The options are:

1. Use the Debian Linux VM (Crostini) that is already present on Chromebooks:

https://chromeos.dev/en/linux

All you do is click on a few buttons in the settings. This approach preserves Verified Boot.

If you want to replace ChromeOS on a Chromebook with a Linux distro, you can use Crouton: https://github.com/dnschneid/crouton

This approach removes verified boot.

1. https://www.chromium.org/chromium-os/chromiumos-design-docs/...