I now think they are just buying themselves a developer community.
As @tchambers and others have pointed out, the size of the entire #fediverse is a rounding error in the user numbers that companies like Meta have and expect, and need to have to make it worth their while to create a new product.
So in a few months or a year, it's very possible that 90%+ of all ActivityPub endpoints will be controlled by Meta, and they will be the de-facto standard.
