First, Usenet was just as much of a dumpster fire as Reddit et al. in some branches (alt. I am looking at you). The rest (comp. soc. sci. etc) were heavily self moderated.
Second, I am not sure the author is clear on what is the primary product of social media, as I see it. We, the users are the product. By moving to a protocol, there is little to no opportunity to capture private information about the product. (Not complexity, too big, or filter bubble.)
Why would a platform give up such income stream?
Am I misunderstanding what the author means by protocol here?