The short answer is that I only support what I use and what my private customers use. I’m not opposed to tkinter it is just that I don’t have anybody who needs it today. So for now I’m sticking with SDL/Bogue, and I’m quite happy to see the 7GUIs response to your 5yr question at Library for GUI? - #50 by Idara_Nabuk.
Aside: The tcltk Windows link you gave looks like someone built binaries without publishing the source or build logic. Other people may be comfortable with that, but as a vendor I’m not. I’m only comfortable with auditable code that has an active maintainer.