'People' is equivocal here. While complex, and (as you point out, in so many words) an evolved standard, the HTML/CSS/JS stack is arguably one of humanity's greatest achievements, up there with the invention of paper, or perhaps cuneiform.
It's imperfect, like all living standards, but it manages to be ubiquitous, expressive, and _useful_. And for those of us who grew up with these standards, they are second nature.
Like piano, mastering these standards gives you the ability to express complex UI concepts with grace and alacrity.
Don't smash up your parents' piano simply because practicing scales is a chore :)
