Many bad things are popular. Java, C++, JavaScript. Popularity doesn't preclude something from being shit.
The front end UI isn't a collection of evolving standards. It's the same standard with more and more cruft added on top.
HTML wasn't designed for what we are doing with it now. Each additional layer... css, JavaScript, the dom, typescript, react, is a new layer over an old thing. It's like never buying a new car just modifying your old one from the 50s to stay up to date. That's why the entire front end API feels so bad. It feels disorganized with complexity that exceeds necessity.
The complexity of the spec even took years for browsers to get right. This is not a sign of good design. It's a sign of endless designs layered on top of each other all in vain effort to modernize everything and keep it backwards compatible.