Even Oculus is saying now they don't expect VR to take off immediately. They're suggesting it will take time to build a consumer base. That makes it a pretty risky business. They need to have content creators to make games (or whatever) for the tech, but those creators need to be able to make money from a smallish initial base to keep producing. That's why Oculus has been courting a lot of indie developers who don't need huge budgets.
Recently Jesse Schell suggested that all the VR platforms are different from each other, so you can't simply port games across; you have to design for each specifically. If true, the market and the developers will be split across Oculus, Vive, PSVR, Gear, making it even harder to make money.