[dsrw]

Essentially nobody was a "JavaScript Developer" in 2005, 10 years after JS's release. JQuery didn't exist yet, the term "AJAX" hadn't been coined, and NodeJS was years away. Web developers were using JS to enhance pages, but it wasn't a language that was widely used to write applications. I don't know what the popularity numbers looked like so I'm not saying you're wrong, but it was definitely closer to 15 years before people started to take JS seriously.

JS aside, I think there's probably some survivorship bias going on here. I don't think there are a lot of 15 year old, relatively unpopular languages that are still under active development. Maybe it's not that languages that don't become popular in 10 years never will, but rather that languages that don't become popular in 10 years tend to be abandoned by their developers, thus sealing their fate.

[pron]

JS was a very popular language in 2006 (at least in the top 10 if not top 5) -- a lot of people were doing at least some JS development -- even though it grew bigger later. Nevertheless, JS (like Objective-C and Swift) is indeed special in the sense that it's the "monopoly language" for a particular platform.

> I don't think there are a lot of 15 year old, relatively unpopular languages that are still under active development.

There are quite a few. If you look in virtually any language ranking, places 10-40 have many 10 year-old and even 15 year-old language. Here are some continuously developed >=15yo languages that are less-than-middling-popular and have always been so: Common Lisp, Racket, Clojure, OCaml, SML/NJ, F#, TCL, Haskell, Idris, Groovy, Squeak, Erlang, D, Ada, Nim. There are more of these than there are super-popular languages. (I didn't include any language that was, at one time, at least somewhat popular but is no longer, such as Visual Basic, Delphi, and Perl 5).

There might still be survivorship bias, but I am not saying all that is fate, just a clear historical observation.