I'm not sure I agree that the DOM is that bad(more that people are using it improperly and for the wrong things), but yeah, modern JavaScript is hardly to blame for anything. The closest thing to an argument I've heard is "mah static typing".
Asking WebASM to be everything, including a rendering engine, is asking for problems at such an atrocious level.
I'm not implying that the DOM is bad (IMO it's one of the most powerful UI systems that I've ever used. Both in what it's capable of, as well as the speed that I'm able to develop and iterate something with it), just that it's BIG.
There's a lot of "legacy" there, a lot of stuff that probably should be removed, or at least relegated to a "deprecated" status.
If people are misusing the DOM API at a fundamental level(to do non-DOM related things), that's not a fault of the API. It's as if everyone has forgotten that DOM means Document Object Model. The vast majority of websites and web apps are not very complicated on the client-side, so I'd say that the DOM API generally does its job well. Trying to do anything that's not about constructing a document or is doing heavy amounts of animation or node replacement using a document-building API is asking for a bad time. It's quite implicitly attempting to break fundamentals of computer science.
Making the API one uses to render pages in a browser a free-for-all doesn't solve the problem, and you end up losing many of the advantages of having actual standards. What would be better is for the browser to provide another set of APIs for things beyond the "expertise" of the DOM. This kind of the case right now in some regards, but there's a reason why React and Glimmer use things like virtual DOMs and compiled VMs. I'd argue that a standardization of such approaches could be a different API that probably shouldn't even be referred to as a DOM because they are meant to take a lot of shortcuts that aren't required when you are simply building a document. In a sense, WASM is intended to fulfill this purpose without replacing the DOM or JavaScript.
Object-oriented programming is quite often misued/misunderstood. Does that mean it's a "bad" concept? I wouldn't say so. Education tends to suck, and people are generally lazy and thus demand too much from the tools they use.
I'm not copping-out because I'm not putting the DOM on a pedestal. Calling it a bad API because it doesn't work well for a small minority of cases is a total mischaracterization. If it was an objectively bad API, it wouldn't have seen the astounding success it has.
EDIT: I'm not saying that programmers are stupid... but that their expectations are sometimes not congruent with reality.
Asking WebASM to be everything, including a rendering engine, is asking for problems at such an atrocious level.