I think such things hit a critical cost which means a possible mass market then mass production then given away with cereal packets like pocket clalculators.
I think HMDs are facing a bit more of an uphill climb as it's such an incredibly niche market. Really, HMDs only have large appeal to people who have a need to move their head around ingame independently of the rest of whatever it is they're doing. Flight sims and racing sims gain by far the most benefit from being able to look around without changing your orientation in game.
I've seen a couple youtube videos of ArmA that were using TrackIR, and while somewhat cool in an FPS, it's not a gigantic advantage over just using mouse control to look around.
Couple that with the fact that people are so immersed in and used to high resolution displays, anything less looks positively asstacular in comparison.
I think in 10 years the main things will be 3D will be pretty much ubiquitous and controllers will be a lot more precise than they are currently.
Wiley.
