> HTML and CSS weren’t designed to be general-purpose GUI description languages
Maybe not, but they are now, and are incredibly diverse in what that can achieve.
> HTTP wasn’t designed to be a client-server GUI application protocol.
Again, maybe not, but it is now with Websockets, http2 and webRTC.
> JavaScript wasn’t designed to be a serious application programming language.
Also maybe not initially but it is now incredible capable and amazingly only 50-100% slower than C! We now have WASM that let you reuse a vast amount of code from desktop too.
> basic UI controls still have to be custom-implemented and custom-styled by each app
Even with native gui toolkits developers are having to constantly build custom widgets for their specific use case. HTML gives us a baseline of widgets what work everywhere from desktop to mobile on all OSs. Would I like more? Yes, but what HTML gives us is the ability to build our own really easily, in an accessible way.
> CSS layout and styling is still a byzantine minefield.
I disagree, flexbox and grid layout are incredible and solve all the issues with the older box and float model.
> The ecosystem of tooling and libraries and frameworks remains highly fragmented.
True, and it can be a barrier to entry for someone new. However newer tooling such as Vite and ESBuild are incredible, fixing menu of the warts of the older tools.
But it would also say the the the amount of tooling options available is a testament to the success of the web platform.
> staggering amount of manpower is being wasted away in bespoke frontend development.
Most people don't want the web painted in the same shade of magnolia. Plus all those supposed "wasted" hours pay hundreds of thousands peoples salaries, supporting family and contribute to a vibrant economy.
The web platform is one of the greatest inventions of all time, and so incredible successful. It's so diverse in its capabilities and surprisingly performant at that. Honestly it's far better than people often give it credit form.