While I don't entirely disagree, how many web sites need the kind of features you're talking about? Have you ever looked at Hacker News and thought "if only this had user-definable menu shortcuts," or been shopping on Amazon and thought "this would be so much better if it had toolbars with custom icons"? Probably not.

One of the most frustrating things about modern web development, at least to cranky old people like me, is the conflation of web sites with web applications. If the use case you're talking about is truly trying to replace what would otherwise be a desktop application, like Gmail or (heaven help us) a code editor or word processor, then many of the features you're talking about start becoming useful. But for so, so many web sites, the focus on feature-rich client side toolkits has become, well, kind of a distraction. Is there any real advantage to the user if the New York Times web site is a state-of-the-art React application? Is it improving my reading experience? I not only don't need them to be using a toolkit that gives them desktop-class drag and drop capability, I don't want it, because I'm just there to read a damn article.

So when you write "web application UX designers are still re-inventing the wheel and without some enforced UI guidelines like Apple had in the 90s websites will never fully catch up with desktop apps in terms of usability," my reaction can't help but be: you literally just used "web application" and "website" as if they were interchangeable, and they are not. There's a worthwhile discussion to be had over how much "desktop-class UX" we actually need for our web applications, but I'd like to see our web sites stop being built like they were web applications when they don't need to be.