Apple, Google, Amazon, Microsoft, IBM, Tencent, Elon Musk, Samsung, Huawei, Dell, etc. There is no shortage of companies who could compete with Facebook on a technical level. Just so far there isn't any. My hope is that Facebook creates the market and other companies come in and diversify it. Otherwise we'll be in some sad dystopia where the only way to get VR is to hand over all of your private data.