Oh, it’s hard. But it’s rapidly becoming commodity hardware. That was in fact the basic premise of the Oculus Rift: that the mass market commodity solution for a very old dream was finally approaching a price point where it made sense. The patents were expiring; the panels were cheap and getting better by the month. The rest was plumbing. Hard plumbing, the sort that calls for a Carmack, maybe, but plumbing.
Rendering is the dream of a game industry desperately searching for a new immersion, another step in the ongoing escalation of immersion that has served as the economic engine of ongoing hardware replacement, the false god of “games getting better.” It was an out: the plucky indie that bucked the big consoles but still gave us the AAA. It was supposed to enable “art.”
But rendering was never the point.