Matrix is for now one of the few actually federated things (in addition to email) that still has a chance of not failing. As such it's a good basis for people to build a Metaverse on top of. Of course it is going to require people actually showing up and doing that. Email completely destroyed it's competitors by virtue of "you can email everyone instead of just the morons that bought the exact same shit that you bought". Thirty years on, nothing has changed. Whatever it's going to be, Zuck's ffing walled garden ain't it.
Neal Stephenson has been repeatedly answering the question what he thinks about the whole Meta thing as part of his recent book tour for Termination Shock. He'd be the person that coined the whole notion of the Metaverse in Snowcrash in the early 90's.
He does not seem very impressed with this effort by Facebook and nor did Facebook bother to even talk to him about their plans. I think that is probably a tactical mistake by Facebook and it kind of outlines how desperate they are.