Can anyone think of why Lenovo would do this? I would expect that this would potentially draw the ire of Google, but surely Lenovo has thought this through and maybe knows Google doesn't care enough? Just curious if anyone can speak to Lenovo's incentive calculus here
https://www.lenovo.com/us/en/faqs/operating-systems/install-linux-chromebook/
(Ps: the guide is somewhat out of date -- for those curious, this seems the way forward for Chromebook users looking to install a Linux distro of their choosing https://docs.chrultrabook.com/
Seems the galliumos project mentioned in the Lenovo link is now discontinued)
I'm sorry, I won't say any more than that due to the possibility of transgressing some long forgotten NDA. But if you can run down any current or former Lenovo employees I doubt you'll have a hard time confirming this. Also note that this was true circa 2019 or so, and went at least as high as the #1 exec in the company's PC division.
Note: they may also resent Google for similar reasons, but I can't speak to that from first hand knowledge.
Chromebooks are pretty open. See official documentation at https://chromium.googlesource.com/chromiumos/docs/+/HEAD/dev... which directs to a third party site dedicated to installing alternative OSs and firmware.