To be honest, I perceive the main problems with the present web stack to not be on the consuming developer's end - writing JSX & CSS is honestly a pretty decent

To be honest, I perceive the main problems with the present web stack to not be on the consuming developer's end - writing JSX & CSS is honestly a pretty decent representation of what HTML/CSS/JS can actually combine to be. Plus modern JS is a half-decent language, even more so when TypeScript is used. I perceive the main problem to be how hard it is on the implementing developer's side - only megacorps can make functional web browsers. That's a huge problem.