No one uses the DOM because they think it’s the best possible GUI technology. They build software for browsers because browsers are the lowest common denominator for distribution, which is far, far more important than technical considerations most of the time. And because of that, there’s also a large ecosystem of well understood, well documented, widely used, beginner-friendly tools for it, ranging from jQuery to React to Tailwind to WordPress.
We can talk all day about how there are better ways to do it, but until you solve the distribution problem, the technology doesn’t matter. Mobile apps sort of solved it, but even then, the bar for installing an app is higher than the bar for clicking on a link. Plus there are cross-platform tech and policy differences to deal with, you can’t guarantee your users are running the same version of the app, etc.
I'm not really disagreeing with you so much as wishing that webdevs had access to a better UI toolkit because the current state of things makes life harder unnecessarily.
We can talk all day about how there are better ways to do it, but until you solve the distribution problem, the technology doesn’t matter. Mobile apps sort of solved it, but even then, the bar for installing an app is higher than the bar for clicking on a link. Plus there are cross-platform tech and policy differences to deal with, you can’t guarantee your users are running the same version of the app, etc.