Many developers feel that with the advent of GNOME 3, GTK has become deliberately developed as a GNOME-only tool, to the exclusion of its other applications. Clem, a member of the Linux Mint distribution’s development team writes, “GTK 3 isn’t a reliable API. Maybe it should be called libgnome instead… I genuinely get the feeling that GTK 3.4 is developed for GNOME 3.4, that it doesn’t really matter if it breaks things and that we’re not supposed to use it outside of GNOME.”
Looks like Gnome devs are not caring and Red Hat seems to be a part of the problem.
"No time for compatibility
When I confronted Benjamin Otte, Red Hat’s developer in charge of GTK 3’s theming support, on this issue, he responded with complete disregard. “GTK doesn’t swim in extra developers that are happy to spend their time ensuring compatibility with rarely used themes. I decided the time was better spent implementing new features than caring about other themes,” writes Otte. Theme developers responded that the “rarely used themes” he refers to are hugely popular, representing many hours of volunteers’ time, and have already been downloaded many hundreds of thousands of times."
Interesting read and thought to share.