A lot of those problems you mention are due to JavaScript realistically being the only language available for client-side web development. It's just not a good

A lot of those problems you mention are due to JavaScript realistically being the only language available for client-side web development. It's just not a good language for anything but the shortest of scripts. It lacks a proper type system. It lacks proper support for namespaces and modularity. It is full of far too many inexcusable flaws ("quirks", as its advocates like to call them), even in such basic functionality as its equality comparisons. It's full of features that are outright harmful. Prototype-based OO has proven, in practice, to be inferior to the more traditional class-based OO approach. It's just one problem after another when using JavaScript. CoffeeScript and other languages that "compile" down to JavaScript may help somewhat, but their JavaScript legacy is still generally quite apparent. Instead of being "good", they're just "not as outright horrible" as JavaScript. Things would be much better if there were a wider variety of languages supported by browsers, including ones with the feature set necessary for effective, large-scale software development.