Sure, until you parachute into a code base where several generations of contractors added features that communicate over a shared global object. This is bad per-se, but becomes worse when your language allows one to add fields on the fly and you end up with this container full of similar fields because eventually nobody knows exactly what’s in the object any more...
And that seems pretty simple to fix. "The same level of awareness that created a problem cannot be used to fix the problem" - and maybe that's why they hired you, to fix these problems. I've been that guy before. What was really fun was the codebase I had to fix that used mexican slang words as variable names, and I only speak English. So much fun. But I sucked it up, accepted the challenge, and I improved it.
It really doesn't take a super-genius to code javascript simply, efficiently, and without errors. Funny that a lot of programmers that think they're very smart are the ones that either shit on javascript, or make a lot of stupid errors with it, or both.
I've seen similar abuses with global maps in other languages (essentially the same). This is an architecture fault rather than a language fault.
As you say, that is a problem with any language and project with a revolving door of developers. Perhaps those companies should learn their lesson and hire at least one or two good, permanent senior devs to keep things on track.
Like always, the human factor outweighs almost everything else.
