I imagine there would be subcontractors upon subscontractors supplying materials and components to the manufacturer (Foxconn?). Oculus' expectation was probably just too high, and suppliers over promised things to get the contract and there probably weren't enough penalties in place in the right place to get things done on time. I bet Apple have some pretty tight demands on Foxconn making adequate numbers of their iphone.
People who are mad at Oculus have every right, but there's probably not a thing Oculus can do, because the manufacturer probably has the same problem with his supplier who has a problem with somebody else down the line and so on and so forth. If anybody watched that BBC documentary on child miners for Apple products, you'd know that there's a miner who digs material out of the ground for 16 hours a day, who sells the materials on to a local factory for sorting, who sells it onto a manufacturer for the component, who has special distributors of whom only they can sell their parts, who then onsell to the actual manufacturer. That's at least 4 or 5 subcontractors (possibly more in the supply line). And in any one of these supply lines, if the business conditions are not favourable for them, they will literally stop production and do something else. What I mean by that is, say the price of steel jumps 10%, (i work in construction), they'll stop production of any steel products until it becomes a favourable business proposition again. Oculus and the manufacturer could jump up and down until they're blue in the face, but money is the only thing that drives them. They'll promise more sure, but its just to get people off their back. In the end its Oculus that should learn to under promise and over deliver. Anyways maybe I have no idea what I'm talking about, but that's how I imagine what's happening. And if you're frustrated you haven't got your Oculus, just cancel. Money talks.