My thoughts as well. Plus the price is roughly comparable to a higher end smartphone. Given the hardware and software involved, it's not terribly far off for a gen 1 device.
I think of the Palm and WinMo phones I paid $500+ for during the early generations of smartphones and it starts to make more sense. And just as I'm sure those devices from Palm and HTC could've been a lot nicer even with the tech of the day, the price would've pushed into the $1000 range. Gen 1 is always gonna be fairly expensive and still not quite as good as you wish it was. With later revisions, price drops and capabilities go up.
The only issue I see here is that rather than looking at relative openness and ability to run in-development software on something like the Vive or the Rift, many people are going to look only at price and wait for something like a $300 Playstation VR headset that's limited to whatever can be sold and approved for a game console.
As I see it, it's still an early-adopter techie toy/luxury so whether it costs $399 or $599, I'd only really buy it if I had that sort of dough in my "fun stuff I don't need" budget. Even as someone who bought a Rift DK2 at launch, I'm both waiting on buying any consumer device and not too concerned with the price difference between a $400 device and a $600 device. If anything ends up striking me as really worth buying, I won't just buy a lesser device to save a couple hundred bucks. I'd rather wait until I see something I really want and will use and not buy anything at all until then.