In fact, because of the lack of standardization on a single toolset or approach (e.g. Cocoa, WPF, etc.), we're in a position to improve well beyond the current SoTA. Some examples:
React.js from IG/FB: One of the first opportunities in the browser to treat rendering as a stateless canvas, freeing us from the complexity of time-management.
ClojureScript[1] - and more importantly, the immutable data structures from ClojureScript, let us simplify our UI programs conceptually. And combining it with React (Om), we can make UI's both fast and simple
Datascript & friends: Bringing entire in-memory databases client-side.
All of these, and the wide-open nature of the web as it exists today, means we're in a position to experiment with radically new ideas and find a much more efficient way of representing our goals. It's a really exciting time to be working on this stuff.
Nevertheless, I upvoted because I do believe we're in a plato's-cave situation with current practices in web-development. There's very little overlap between the desktop and web world, so many of the lessons haven't carried over - how to manage complexity, the important of tooling, etc. But we're making our way, bit by bit (or more recently, leap upon leap)
[1] I'm admittedly biased as I've put considerable amounts of effort into the project, and it's not without its warts. GC pressure can sometimes be very tough, and the tooling needs a lot of work.