Tcl is a dying language. In the free marketplace of ideas, tcl lacks the community of fans as well as corporate support (see the languages invented at Microsoft, or the huge push in JavaScript from Google's optimization of V8 and thus Node.js as well as Go from Google, or all the large web companies who help PHP dominate most of the software running the web, whereas Tcl's was once sponsored by Sun who then spawned Java and then died/got swallowed by Oracle). Also, tcl sucks.
There was a time (in the 90s) that Unix graphical programs were all universally ugly and many used the Tk...