Things like mastodon represent a Jailbreaking of the captive user. If the goal is to monetize the consumer as the product, you could do no worse than to free that consumer from the cattle yard and offer them the ability to graze at their discretion alone.
Given regulatory issues with data sharing between different Meta properties they have a massive incentive to add activitypub support. It would be an easy way to appease to the regulators.
Maybe the goal is to create a new social network to fill the void that Elon’s Twitter 2.0 left. Maybe a company can actually do a genuinely decent thing every once in a while…
Sure. But I have zero confidence, based on previous actions, that company is Facebook/Meta.