> but there's absolutely nothing that requires there to be only one metaverse.
Aside from how it was specifically used, the way the word is formulated alone suggests there should only be one. Meta loosely means above, and encompassing, on a higher plane. Verse comes from universe obviously. The unified world, above everything.
This is just another case of people confidently misusing words so prominently that the meaning changes, which "is allowed", obviously.
> a metaverse is just a persistent virtual space shared among multiple users. We have lots of those, and have had them for years
Yes, we've had them for years, and we didn't call them metaverses, and nothing was lost in that time. That's good evidence for my prior assertion that the word (with its new definition) is practically useless.