Anything doing server-side work is going to have to be at least somewhat custom. The main problem is there isn't a standard "combobox" at all to speak of: we're still mostly stuck with the same carved-in-stone widget set from Mosaic, whereas native toolkits were more inventive even in the late 80s. Where's Athena's 2d panner widget, for example?

I didn't read any satire in the article at all, it just laid out all the built-in behaviors that a proper button has, and how much work it is to reimplement all of them. Something declarative and CSS-like would have been ideal for customizing elements, but instead we got the half-assed Custom Elements API and the completely different DX atrocity that is Web Components.

I can't really fault Custom Elements too much though, it's an imperfect API for an imperfect DOM and it's better than waiting forever for perfection. But I don't extend the same generosity to the Web Components spec.