Not only all the things you mention, but I kept thinking "Well, if they do manage to make a pivot where they are nothing but infrastructure and still manage to please Wall Street, then good for everyone:

• Users will have a way to move out if they want to do so.
• Companies that want to keep a social media presence will be able to do it from their own domains, while not having to worry about the operational aspects.
• Decentralization is still preserved.
• Transparency is still preserved.
• By becoming infrastructure, it basically means they will become a commodity which will have to compete on price. Sure, one could make the case that AWS (and Azure/GCP) make real money by providing other services on top of their “basic” hosting offers, but no one looks AWS and think “AWS is locking people and charging crazy prices on S3 but they can’t get a compelling alternative”.

If anything, all these “what if scenarios” are almost making me wish that Zuck does pull it off.