Maybe this is a hot take. However, a lot of the Chromebooks that were deployed by schools during covid are build like tanks while being super lightweight and having great battery life. Meanwhile the old thinkpads are 10 years old and are probably starting to wear down. Many Chromebooks support coreboot these days so theoretically they have the potential to be more private and secure. Some of them are also arm which means that they are more efficient from an architecture perspective.
Edit:
I like how incredibly controversial this is. I have successfully split the votes
There’s certainly a case to be made for saving Chromebooks from the landfill by installing Linux. There will be plenty of people who will be happy to have one. But that will be a different target audience than the people who use old ThinkPads.