The “extend” part is fundamental before they can actually get to the “extinguish” stage: https://ploum.net/2023-06-23-how-to-kill-decentralised-networks.html

Once Meta joins in, a new set of dynamics are going to develop between old fediverse uses and new meta/fediverse users. If Meta adopts an “EEE” approach such as the ones described in the article, there’s going to be disruption in the user experience from which the fediverse might never fully recover

Edit: clarification on the last sentence, my main concern is that a growing niche protocol such as ActivityPub might be destined to irrelevancy after Meta is done with the Extend & Extinguish, similarly to what happened to XMPP