Excuse me but the cost of producing stereo sound and the cost of producing stereo 3D world in fullHD on each eye has really nothing to do with each other. Cheap speakers are easy to make, cheap VR sets and cheap equipment to produce good enough VR is nowhere near available at a cheap price.
The first walkman cost 700$ in 2014 dollars (199$ in 1979). VR sets are not gonna be expensive forever, in 5-10 years your smartphone could probably power it and the device would not be larger than a a pair of sunglasses.
What they have in common is economics. I had to replace a broken smartphone in a hurry last month and I just got the cheapest thing that runs the latest version of Android. I paid $75, not on a plan. I got a slight discount for being a long-time customer, but I think the RRP of that phone is only $99.
VR headsets will be cheap and basically disposable accessory within 10 years; I'm pretty sure they'll be available for under $100 by end of the decade.
