I'm not really disagreeing with you, just saying that full coverage isn't important to some people. I feel like the available analysis tools for Angular are pretty good. There are definitely some gaps, so maybe I'll change my mind later, but the advantages of its data binding are greater than the advantage of being able to use more analysis tools for my purposes.
I don't just mean code-completion and debugging, but things like validators/linters and other static analysis tools; code coverage, formatting, refactoring.
It's not a good use of time for every IDE to try and implement every one of these for every crazy JS framework.
If we stick to using languages as they're intended (and defined), we'd have full coverage for these tools.