The difference is Instagram and WhatsApp were products that had real product value before Zuck acquired them.
Zuck has to build a v1 product from scratch with the Metaverse. When's the last time FB has truly built a revolutionary v1 product? It's not really in their DNA anymore. I'm not saying they can't do it, but I wouldn't point to IG and WhatsApp as examples of why Zuck can pull it off.