Most Chromebooks from the last 5 years have 8 GB of RAM and 32/64 GB internal drive. That’s not enough to satisfy the kind of user who would buy a Thinkpad.
I have 4 Chromebooks that I converted to Linux, from the era before the aforementioned, with 4 GB of RAM and 16 GB of internal space (and just 1366x768 res – kdenlive and some cad apps don’t fit in that res, not even some of the DE pref panels fit!). At 16 GB internal disk, only Debian fits in there properly. Mint and all ubuntu-based ones, or fedora are either out of space, or with only 1 gb left (Debian leaves 8 GB free). Also, it’s near impossible to use a modern web browser to browse the web with 4-5 tabs at the same time at 4 GB of RAM – you always hit the swap sooner than later. So it’s literally bare bones experience.
The newer Chromebooks, with 8 GB RAM and 32/64 internal space are definitely better, but still nowhere near the “modern” specs required to run Linux properly (especially if you also want to do some video editing). In fact, look at the Cosmic DE. While it’s new, and without any code fluff, it requires a minimum of 2.4 GB of RAM just to boot (which is more than gnome/kde).
So yeah, Chromebooks have nothing on Thinkpads. Not for the kind of users who buy thinkpads anyway.