I suspect that the dominance of HTML is largely due to it being the only browser native markup language. Crucially, the browsers' dev tools always show HTML and

I suspect that the dominance of HTML is largely due to it being the only browser native markup language. Crucially, the browsers' dev tools always show HTML and having an obvious mapping from there to your code is hard to beat. I personally dislike HTML due to the verbosity. I prefer hyperscript.