Who do you feel React is hurting, and in what way?
There's an entire open source community that revolves around "React alternatives that exist because they're not React". For better or worse, people have ideological reasonings for their choice of JS framework. I've seen it play out countless times at multiple jobs between people who just want to get their work done with the industry standard tooling, and people who have a bone to pick with FB and become fanatical about using Vue/Svelte/*whatever instead of React.
The contrarians usually win out, because the people who just want to do their job and go home don't care enough to fight that battle over and over again. The result is a patchwork of forgotten projects and frozen dependencies that no one knows how to maintain, and a security nightmare where everything is pulling in tons of random unmaintained NPM packages with 4 GitHub stars, rather than the battle tested 5 year old React equivalent with 2k stars.
To be fair, this happens with React too (all the time). It has more to do with the JS ecosystem than with the framework of choice.
That's exactly what they're not doing
I like Angular's approach the best. You have an HTML file, a SCSS file, and a TS file. The TS file is essentially your model and handles all the thinking. HTML/SCSS are kept declarative like god intended.
React itself is just function calls. JSX makes the function calls look like HTML. HTML is generated from these function calls at runtime.
Anyway, what editor are you using that doesn't support JSX? It has support for it in the major IDEs.