I'm trying to figure out if this is serious or parody. You do know that RSS is a spec, not a brand, right? Right?
All things you are trying to get others to use have a brand, whether implicit or not. Heck, it's usually even valued separately from the technology (good will, etc).
RSS, the spec may be fine. I've implemented RSS readers, heck, i use newsblur every day still.
RSS, the brand, is a goner.
The OP (and twitter post) is complaining that others consider the brand dead, and are arguing that the use case it covers are unmet by other things, and that the spec is still good stuff. Those are all very orthogonal things.
It's great that the spec is still the right thing! But the brand is dead, so you won't get anywhere without fixing that.
If enough people think that RSS sucks, is too old, died with GReader, has no user-base, or whatever other story, why would they invest their time and effort in supporting it? If the problem isn't technical, then it might need some kind of marketing solution to get over the historical baggage in the zeitgeist.
This whole notion of RSS' "brand" being the problem just reeks of a used car salesman trying to convince me that spare tires are for chumps.
The world is littered with highly useful technologies that nobody adopts, or eventually die to less useful, arguably objectively worse technologies. Adoption and software life cycles are not a techo-meritocracy.
In short - you are completely and totally ignoring the social aspects of software adoption and use. But they are, in fact, often the most important part. I don't actually particularly like this any more than any other software engineer - it often feels wrong. That does not (and will not) make it any less of a reality.
(as an aside, yes, in fact, as joist hangers and ties and such became more and more required due to code or construction method, structural screws became all the rage - nailing joist hangers/etc with regular framing nail guns was hard and dangerous, but structural screws just require an impact driver or a screw gun to do safely. Now they actually have specialized metal connector nailers, so structural screws are getting ignored again outside of decks)
Usefulness isn't a high enough bar. When choosing a technology, I might also want an active community, for support, for ecosystem tooling and integration, and more.
Things with a reputation of being dead gains lower interest and support.