> The purpose of Open UI to the web platform is to allow web developers to style and extend built-in web UI controls, such as <select> dropdowns, checkboxes, radio buttons, and date/color pickers.
> Today, component frameworks and design systems reinvent common web UI controls to give designers full control over their appearance and behavior. We hope to make it unnecessary to reinvent built-in UI controls
But the lack of a combobox in HTML, I don't get at all. datalist kind of sort of does it but not quite, plus it's inconsistently implemented as to what it actually shows.
If there were a standard, you'd probably still complain that it doesn't match your use-case.