When people tried to write big enough applications with JavaScript, they found out, that it was a mess. JavaScript is a terrible language, so another languages were born (including modern JavaScript which isn't that bad). DOM is a very low level and very verbose API, so various approaches were taken to simplify development, e.g. jQuery, Angular, React. Hello world apps might be easy to do without frameworks, but once you're making complex pages with dozens of inputs, asynchronous loading, etc, lack of frameworks is likely to turn your code to a mess. Or, if you're brilliant developer, you might invent your own little incomplete buggy framework.
It's similar to WinAPI. Sure, you can write C with WinAPI and it's enough for simple applications. But in practice people use better languages and frameworks.
Simple JavaScript has its place, of course. If I'm making text-only website and I want to introduce just a little bit of interactivity, like image gallery, using anything but a few lines of JavaScript is overkill.