Browsers and JavaScript are what we have, we can't magically replace every browser and JS implementation in the world. We have to figure out where we want to go and slowly get there. That is exactly what is happening in the frontend world and that is why there is so much churn.
Browser apps have to work across 4 major browsers with versions going back almost 10 years, an infinite amount of screen sizes, and a near infinite amount of devices. There is no other platform with the capabilities of the browser that has this much reach.
If we had the ability to start from scratch and build the ultimate web platform, yes, it would probably be way better than what we have, but we don't have that ability nor will we ever have it, so talking about it is a waste of time. We need to look at our current capabilities, where we want to be in the future, and iterate until we get there.
All of the tooling we have serves a purpose and solves a problem, it's not like frontend devs are adding tooling for the fuck of it.
Take a common stack nowadays: React, Redux, Webpack, Babel, Eslint, Yarn, Styled Components
Every single one of those tools in the stack make my life easier. I don't have to use all of them. In fact, there was a time where I didn't, but I would never want to go back to that time because these tools allow me to build way more complex apps way faster than I used to. And the other great thing about these tools is you can add/remove them as needed. Take something like browser prefixes, as browser support for certain prefixes or features are implemented at a large enough scale, the tooling for that becomes obsolete and you drop it.
And as far as JavaScript goes, pre ES6 I would agree, it sucked. Post-ES6, I will have to disagree. I love writing JS nowadays.