HTMX breaks the "separation of concerns" paradigm. It's not going to help anyone doing anything complex, and it's going to be a crutch for anyone getting started. It breaks down quickly when the problem is anything more complex than clicking a button to load some content, and then what - rewrite everything in a more capable framework?
That's like preventing HTML5 to include a native date picker. Because if you want anything more complex than a basic date picker, then what? Rewrite everything in JavaScript?