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.
Exactly. The ARM Chromebooks can run coreboot in a lot of cases. I am not sure about WiFi and GPU acceleration but at least those can be isolated if necessary.
Coreboot does not remove IME. Libreboot (a coreboot distro) does. Or neuter it.