A large corporate shopping mall settles in a nice neighborhood with small local run shops and community centers. The new shopping mall says ‘if we settle here, more people will come, and you all will benefit’. A few years later all small shops are bankrupt and the community is destroyed. What remains is a barren corporate landscape.
I think it could be a threat to mastodon like how Google was a threat to xmpp, have you seen how many instagram users there are? And all of them will be able to make a threads account, threads would easily be the biggest activitypub software.
Yes, the real risk here is that Facebook takes over the activitypub standard with its massive userbase