If things continue as they do, the whole company will collapse. Better to throw whatever they have at a solution than to just lie down and die.
Companies accept that all the time. It's far more profitable to slash investment and turn something into a cash cow over the next 10-15 years than bet the farm and lose. It's actually in shareholders' interest -- which is why so many shareholders have been upset about the VR pivot.
He was only able to pursue his metaverse vision because he has shareholder control, and given the change in stock price it looks like increasing numbers of investors are no longer interested in a company he has total control over.
If that's true, then they're doomed.
Their real problem is that their entire business model is in danger. What they should be throwing their money at is changing their business model, not trying to invent a new field to apply it in.
It still doesn't change the fact that it was a dumb decision. Facebook would have been much better off simply accepting that they couldn't control the hardware or OS or app stores and continue to do the best they could within those constraints.
Instead they just threw away a ton of money that could have gone to shareholders and employees instead.