Yeah, I feel like Deno will reduce dependency usage, and people will hurrah and say "look, using URIs as deps actually worked to make things easier!", when in reality the reason dependency hell freezes over is because Deno actually has an STL.
The problem with adding to JS’s stdlib is that it’s interpreted. If the next ECMAScript version provides new features in the stdlib, it’ll take a while for browsers to adopt it, and during that time, you’ll need polyfills.
Compare that to a new version of C++ where you just update your compiler, and the executable runs (almost) anywhere. No polyfills to run it.
I think the problem is less that it is interpreted and more that there are many different interpreters for different platforms, all of which are competing.
Python is also interpreted, but there isn't much problem changing the stdlib because CPython runs pretty much everywhere you need it to. Sure, there are other interpreters like PyPy that also need to implement changes to the lang, but it's not a show-stopper like it is with browsers.