Earlier quoted context omitted.
You're forgetting spam. Spam destroyed all those first generation federated systems. IRC survived because it was too niche for spammers to target much but spam is the primary thing that killed Usenet and email as a truly open system. The closed systems were better able to fight spam because they could easily ban people and IPs. On a deeper level spam, "brattish" commercial sites, etc. all come from when money got inv…
> Money changes everything. And almost always for the worse.
All the old systems had no channel at all for profit making, so it made it's own in the form of spam and similar.