I don't have a VR headset so I can't speak from direct experience about VR, but I don't buy the author's argument that the disparity between the divergence system and the focusing system makes elimination of nausea impossible. I have two pairs of single-vision prescription glasses: one for walking and driving, and one for looking at computer screens. They have different focusing characteristics, and yet I can switch from one pair to the other without any disabling effects. Hell, I even wear a set of bifocals sometimes and switch back and forth from one second to the next. Some people even like wearing "progressive" lenses that have continuously varying focal lengths from the top of the lens to the bottom of the lens. Lots of people like using reading glasses too; I've never heard of anyone getting sick from that. I think the author is underestimating people's ability to get used to different focal lengths.
I've never used a VR headset, but I imagine that most of any discomfort would come from the headset's fitting closely around the face to block out ambient light. I'd think a true addict might instead just use a loosely-fitting non-light-blocking headset in a completely dark room.
The organization that administers the centralized ledger could be bribed with a value greater than the transaction amounts. One could say "yes, but regulators..." - then one has to add the cost of the regulators, courts, jails, etc... It would be interesting if it turned out that the technical cost of a safe bitcoin network was the same as the human cost for a centralized network. I'm going to think about this some more.