The people stewarding the Web platform have neglected a lot of nice things, among them this—a major version two major versions ahead of what's in browsers, is eight years old.

That it still has any use on notable sites at all seems like a decent cue to at least try not neglecting it before declaring nobody wants to use it.

... however, it's mostly useful for doing things that owners of walled Web platforms have no interest in, like working with interoperable protocols & formats. They've been killing those through active moves and neglect for 15 years, so why would they do something that makes that easier & nicer?