Perhaps your organization believes this: "Tcl seems to be an interesting language, but if we use it to solve a problem, then we'll forever be at risk for losing all our Tcl expertise with no effective way to replace it." Your organization would be correct, of course, in its awareness of the strategic nature of its information technology (IT) assets.
Tcl's part of the solution, though, not part of the problem.
[Explain contracting possibilities, acknowledge hiring mis-practices, distinguish Tcl "learnability" from C++, ...]
RS Tcl skills are less frequently in the market than, say, Java, but
Re the "mastering" side... seems to hold for all programming languages. Maybe that explains why people stick to what they know, against all further reasoning? -jcw
[Explain radical claim that Tcl can be so much more productive in apt problems than, say, Java, that a company will find it cheaper to maintain a solution coded in Tcl, even with the cost of learning Tcl from scratch, than applying its in-place Java expertise on the comparable Java-coded solution.]