Either everyone uses HAML or no one does IMO.

Developers like to copy/paste UI component example HTML from Tailwind/Bootstrap documentation, they like predictability/portability. They don't want a project that's half HTML and half HAML...ie, Vue/React using HTML/JSX vs 50% of Rails views in HAML, 50% old ones in HTML.

Just like how using Vanilla JS is much smoother and reliable than using the latest wrapper framework.