Eh, IMO I don't think that would have worked - I suspect it would have raised too much anti-trust attention and not have been allowed.
The bigger picture is that in the UK at least, 'Meta' owns most communication channels that I use to communicate with my friends. TikTok isn't really a replacement to insta/whatsapp/Facebook, it's a replacement to Youtube.
I think Facebook is using the 'metaverse' as a metaphor to mean 'Facebook owning all forms of communication, as much as possible, both traditional messanger/audio but also extending into the real world as much as possible, and new media'. In that case, I think the metaverse is a much broader play (that nobody else can easily make, and that probably raises even more concerns!).