"It's not our evil plan, you people are already doing it" is the typical argument for Divide and Conquer. Unsurprisingly they bring that argument too:
"For instance, fediverse advocate and co-editor of ActivityPub Evan Prodromou @evan created a paid Mastodon account (@evanplus) that users could subscribe to for $5 per month to gain access. If heβs on board with paid content, surely others would follow."
(the irony being of course that Evan did this with standard ActivityPub, no changes needed)
I have raised the alarm bell already several years ago. Explained how the (at that time mostly dormant) Working Group at the W3C that is responsible for #ActivityPub must be reinvigorated (that happened) and must became a loud defender of the #fediverse (that didn't happen) or else we risk losing our ecosystem to fragmentation and infighting.