Modern ECMAScript is still stupid, yes. Weak typing is 100% a bad idea, and no new language would take this approach. It has, however, obviously improved to the point where it's actually quite okay to use – a modern ES7 app exploiting features like class sugar, async/await, improved syntax etc. is perfectly serviceable, alongside a linter to prevent the stupid features from old versions biting you.

But a whole bunch of 'serious' applications have obviously been written using JS, and it's a totally stupid view to think otherwise. Frankly the people who are the most concerned with 'my language is better than yours' litigation are by far the least productive developers I've encountered.