Couldn't agree more. A powerful IDE with rich, intuitive, self-discoverable, user friendly design tools, debugging and refactorisation is as important to me than the language itself.
And I'd say a third thing that matters as much as IDE and syntax is the wealth of libraries. Not just common things like consuming a rest API. But also specialised things like dealing with spreadsheets, music, whatever your domain cares about.
That gap is closing – e.g. VS Code has refactoring, definition lookup, linting, etc. support for Python, JavaScript, TypeScript, Rust, etc.
It’s still not what the top IDEs can provide but it’s way more than syntax highlighting and since everything is open source it’s improving a lot faster than the commercial market.
You can get shitty support with just syntax coloring for anything and anywhere of course.