"Tcl had its heyday in the 1990's, due in large part to the power of the Tk toolkit and the awfulness of the other X Window GUI toolkits; Tcl/Tk was the easiest and most powerful way to create GUI apps. Unfortunately, Tcl didn't make the jump to the Web, and most of the applications for which people would have used Tcl in the 1990s became Web applications."
"I think the most widely used programming languages have come not from the programming language research committee, but rather from people who build systems and wanted a language to help themselves. PL researchers tend to create languages that are useful for PL researchers: they […] aren't usually useful for real systems. Systems people create languages that are useful for systems builders, so they get widely adopted" ⸺ John Ousterhout
"Jim Clarke and Marc Andreessen approached me [John Ousterhout, the creator of the Tcl programming language] about the possibility of my joining Netscape as a founder, but I eventually decided against it (they hadn't yet decided to do Web stuff when I talked with them). […] If I had gone to Netscape, I think there's a good chance that Tcl would have become the browser language instead of JavaScript"