@kissane 1000% this.
To take a small part of what you're saying and to be massively reductionist, as far as the technical stuff, goes:
RSS = Software-agnostic "what's happening with my website"
ActivityPub = Software-agnostic "what's happening with my website"
atproto = Software-agnostic "what's happening with my website"
It would be way healthier if we framed the distinctions more like those between JPEG, DNG, and PNG.