[raxxorraxor]

I believe the complexity often stems from historical development as well. There are often multiple ways to achieve the same thing or workarounds for specific browser. Either you have HTML tags to format something or you can do it with CSS. CSS is difficult, because there are obtuse rules. The order of CSS-rules is relevant as well as the specificity (which is hell in my opinion).

You can write an extremely clean and awesome HTML/CSS document. But you very rarely find that kind on the web.

I think we neglected being more careful here because browsers became more and more forgiving. So they often render as intended, but not really like it is stated in the often invalid document. That made browser insanely complex as well. No new browser will ever be successful if it would be parsing strictly. More than half of all websites would probably stop working correctly.

I believe you could replace both HTML/CSS with something much more clear and as capable. But on the other hand we should be glad that we have standards like this and perhaps we shouldn't let perfect be the enemy of good.

Perhaps JS doesn't qualify as good, but on the other hand I think its success speaks for itself. It even grew beyond the browser and some electron apps are extremely well received (apart perhaps by your system memory). Despite that, it is a scripting language and it should mostly be used as that. Since every browser comes with a parser, it is a quite mighty tool to have.

Python is a similar contender. It is the ultimate choice for certain domains and I don't see that changing any time soon, even if python isn't perfect itself.