I'm reminded of the master-class hissy fit Harlan Ellison threw when The Terminator came out. He sued, claiming ownership of the general concept of robots from the future. I'm not sure how it shook out, legally, but to this day the T1 film credits include the producers' "grateful acknowledgement to the works of Harlan Ellison."

So there's certainly precedent for Stephenson to claim the moral rights to a "metaverse," whatever that is.