These systems were decided upon in 2003 according to the article, so that's a very different landscape when it comes to "well understood and debuggable" and the

These systems were decided upon in 2003 according to the article, so that's a very different landscape when it comes to "well understood and debuggable" and the language features of the day. As for speed, yeah, that wasn't a feather in JS' cap in 2003. It was notoriously slow and awful in even cases where the script engine was embedded into decently written compiled code. V8 wasn't an option because it couldn't have been for another five years. Regarding the standard library being small, that's not really about the language but about the deployment of it. V8 offers standard library features you don't get in browser-based JS, you get different things in .NET Core vs .NET Framework, you get a different experience compiling C++ on glibC vs MSVC++'s STL, OpenJDK vs Oracle JDK, etc., etc. Those aren't strictly language features. You could take Python and rip out all of its standard library in order to have a more "pure" language approach. Clearly it met specific requirements that the engineers had as a scripting language than others, so it's getting the job done. I just don't think your overall points are actually based in the reality of Javascript as a language in 2003.