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.
The problem with chromebooks is that the base specs are pretty shit. A lot of them have 4 GiB of RAM and maybe 16GiB of disk if you’re lucky.
They were designed to be thin clients to connect students to the internet, and little else. Maybe they could be hacked into something useful, but I don’t think it’ll ever make a good PC. They were always destined for the landfill.
Meanwhile, the best thinkpads were quality machines back when they came out. IMO, that’s why they’re still so versatile today. Free software can’t fix bad fundamentals.