[hardwaresofton]

While TCL does a good job gluing together IC tools, there are many languages that are much more expressive, powerful, and even just as simple (with good DSL support), with larger communities and more modules to choose from that aren't being used because TCL is. TCL has always seemed to me to be the incumbent that prevented uses of more modern languages.

I can't think of one thing TCL does better than any of the languages that come after it that warrants keeping it around, outside of super easy C bindings and some light metaprogramming capability.

A lack of good resources on TCL also leads to people learning it all sorts of ways, and writing all sorts of (often buggy) code with it. Maybe that's just symptomatic of the companies at which I've used TCL, but I think it's pretty clear that there are way more good resources on something like lisp or python than there are on TCL (I mention lisp because if you squint and replace some [ ]s with ( )s, TCL looks almost like lisp)

A lot of my reasons aren't quite concrete, but in short, I think using an almost-dead language like TCL leads to stagnation of a code base. People aren't pushing boundaries, doing new things in TCL. There's definitely nothing wrong with having a no-surprises go-to language that just gets stuff done, but I just don't personally find TCL stimulating.

Maybe I'm just too much of a new-shiny-language hipster