It's a strange move given Facebook changed their name to promote VR and the Quest is their flagship device. Also surprised that after mass producing this device for almost 2 years their manufacturing and supply chain costs aren't dialed in enough to maintain the current price. The message here is that VR is 'failing'. I hope it's not, but that's the message with this backwards move.
Given the stated focus of the company (to the point of renaming to highlight VR focus) I would imagine it's the supply side of the equation.
Also another callout is that I believe Quest 2's have been getting passive upgrades, with newer models having more base storage and other small enhancements.
Another callout is that its common wisdom that advertising is first to be cut during recession, so this might be pre-emptive belt tightening sense their projections show its not palatable anymore to take the same level of loss.