Palmer said they are not making any money on the rift, because they are using custom materials and the rift is, and i'm quoting directly, "obscenely cheap for what it is".
From this the only conclusions i can get to is either Oculus has been engineered inefficiently (which i don't believe), or it is using significantly higher quality materials than PSVR, which is profitable per unit sold, (which i don't believe once again), or Samsung is ripping off Oculus with their deal for oled display supply. Another point that i thought of and maybe that's why Oculus is sold at a loss (or at least not at a profit) is economies of scale and how big production volume actually is for Sony/Oculus. If Sony need to produce more units to cover world wide demand they can decrease the cost per unit produced, whereas Oculus and HTC might have a more limited target audience (US primarily, high-end PC) and they don't need/want to produce as much. The basic idea behind this:
I'm just assuming from what Sony and Oculus figureheads are saying though so it may be something else entirely.