I can’t imagine that meta aren’t already collecting fediverse data. It’s an existential threat to their business model and the data is comparatively easy to harvest. I’ll bet their internal user model already has records for which federated services a facebook user also uses. There’s not a lot of privacy here!
But the cool thing about open standards is that there’s a clear pathway to creating an everything app. Especially if decentralized ids gain some traction, then we could have an app that combines mastodon and pixelfed but presents the different posts in a sensible way.
I can’t really wrap my head around what such an app could look like, but it’s much more feasible to build one than it would be with closed services. I’m hopeful that freedom to experiment without lockin will lead to some really neat ideas