The thing that would make a Metaverse interesting is if it acted as glue between all those very similar services, i.e. being able to hop from one MMO into another one with your complete party, without having to switch accounts, avatars and all that. Kind of like your browser can access and follow links to numerous different websites, but with 3D and multiplayer included.

The problem with Meta's Metaverse is that that's exactly what they don't want, their vision of VR is one where the have complete control over everything. Thus you aren't even allowed to access their Metaverse with hardware not made by them.