So you'll need to factor in higher framerate 3D projectors. For gamers and immersion, 3D is going a be a huge plus.
Really? That doesn't seem to be the case, but probably a different discussion.
That makes no sense to me. You're talking about cave as a commercial venture, for a professional userbase. Why will they want to use four-wall projection in a cluttered room instead of having a room for the job? That can be done without any need for Illumiroom. Illumiroom is attempting to filter out the imposition of furniture, or use it to artistic effect, and in that environment four wall projection makes no sense.
Which isn't what cave projections are about. They splat the same resolution everywhere and waste all that rendering behind you and to the side of you. An HMD only concerns itself with where you are looking. I even expect eye-tracking and foveal rendering to be easy to incorporate into an HMD, which'll be much harder to manage in a multi-projector setup.
So in summary, in the consumer space HMDs are clearly the way forward for full 360 VR immersion. In the commercial space, there'll be different pros and cons for different systems, but Illumiroom isn't going to help really. It could be used for some niche purposes, but it provides nothing for 360 degree imaging where you'd clearly set aside a blank room for that. Illumiroom is something else that may have it's time in the sun but is destined to be phased out, unless people decide the fashion with video interacting with furniture is the future.
Being a console forum I was talking about consumer implementations. I am not saying IllumiRoom is a replica of a cave, but follows it's principles. It DOES allow for cheaper caves however as it brings consumer level tech into this area.
From a commercial perspective there are plenty of applications for something that works in a cluttered room. There are many more simulator users than there are users with dedicated clean rooms.
We sell a flight simulator that splits into three sections so it can be wheeled into storage which with many of our clients is just the side of the room. The space is needed as many sim labs are shared spaces.