"And don't tell me it's because there are no alternatives."
Then I don't know what to tell you. Why do you dismiss this as a reason?
Those are some of the alternatives - at the end of the day most people seem to prefer going back to straight HTML/CSS/JS to build things. They're not perfect but they're pretty easy to learn, they separate the concerns of content, presentation and logic, and they work everywhere (sometimes with a little help from jquery or modernizr).
Transpilers are reasonably popular, but they're band-aids over the real issues, and are susceptible to inherit the problems that the shaky foundation lies out, and the mechanisms for library interoperability are not always stable. These problems also persist in the ever evolving landscape of JS frameworks, which are symptoms of the limitations of JS.
The other side of it is about what works in the commercial landscape. Building around an uncommon tech stack is a risk when it comes to hiring. The widespread nature of JS is part of what keeps it popular, but that's not necessarily based on merit.