First of all, AR/VR is a tough problem space, often for reasons not immediately obvious to common folk. Second, Facebook in my opinion is a wrong home for long-term efforts that may not bear fruit for many years, with its 6-month attention span of employee performance management and its "move fast and break things" culture (both of which clashed with the meticulous hardware-oriented Oculus culture). And finally, a significant portion of people working in AR/VR didn't believe in AR/VR as a product. Some were there for the gravy train, some were there for interesting OS work, some were there for bleeding-edge technology, but I'd say less than half would say "we're working on something that people will love and pay money for". To me it felt more like well-funded academia even and less like a startup (which it was supposed to be).