Meta kind of doesn't have a choice. The major platforms are now owned by Apple, Google, and Microsoft (and also to a lesser extent IBM and Amazon). The strategic risks of being dependent on other companies' platforms are huge. Meta is desperately hunting for a disruptive innovation that will allow them to control the next major platform. A lot of people are betting that will be AR/VR but it could be something completely different.
The number of employees who can see failure coming does not matter when they are organized by hierarchy and coerced to work toward failure under threat of losing their wage.
Speaking from the perspective of a person who is very into VR. There are a lot of things that have gone wrong. First, Facebook/Meta pushing hard with low-end hardware that caused the existing VR gaming to take leaps backward. PCVR was progressing fine before Zuckerberg intervened. Now the VR space is just cluttered with so many low effort, low res games. None of the big players want to get involved, because everyone is so convinced it is too "niche." Meanwhile, you have people who really want to spend money on VR and there's nothing worth spending the money on.
Watch out, the VR mafia is gonna get ya!
Seriously though, any well informed and level headed person could see this coming a mile away. Apparently, such people are in short supply at Meta.