GTK++, stability, and the uncluttered future

What does that have to do with anything? Things that are ahead of their time are often cannibalized by their more-popular siblings and left to die. Many of the languages of the 1960s were way ahead of Fortran and Cobol; not one of them is still used, while Fortran lives, with object orientation no less. (If you don't count C, at best a language of the tail end of the 1960s.)