It's a big commitment to strap a giant, heavy device on your face with 3+ cables to your PC
Granted, but then again, a lot of particular prominent, even more special purpose successes require a pretty big commitment. Rock band did well and no one is going to claim it's trivial to whip out the guitars and drumset. Granted their success did not endure, but primarily because the experience lacked sufficient variety, it did show people were committed to go through some hoops. Similarly, *really* sitting down to enjoy a feature length movie requires some commitment (doing so without commitment is possible, but much less enjoyable.
there aren't many games in the Steam Store that support VR today
And there weren't many games that supported accelerated 3D graphics when 3dfx voodoo came out. Being too discouraged by that leads to a chicken and egg situation. It's probably also off putting that the set of available titles are at best adaptations of existing games or very basic things. The reason being that the quality games take longer and as such are still in progress (Star Citizen is one I'm really looking forward to). Crystal Cove demonstrates they will have capabilities the dev kits aren't even equipped to help publishers prepare for yet. Oculus is doing the only thing that might have a chance, building up a lot of excitement and coming in at an approachable price point to try to break the chicken and egg situation.
Having your eyes so close to the screens means the display is effectively very low resolution.
This is one area that has me pretty worried and waiting (that and the availability of good positional sensing). I'm really hoping they will be able to use at least a 2560x1440 OLED display (thanks to the mobile resolution pissing contest, Samsung looks ready to announce a shipping product with 2560x1440 at 5.2", 560 ppi seems very promising to construct a display out of, even if magnified).
VR is a surprisingly anti-social hobby, even by gamer standards
Very, very rarely is gaming remotely entertaining to mere observers. A lot of very popular things are *always* equally anti-social (texting, reading books, listening to music on headphones, pretty much doing *anything* on a smartphone or even tablet, laptop, or computer).
Notice how quickly we get into geez-this-is-a-lot-of-equipment territory.
The same can be true of racing or flying games, but that doesn't stop the vast majority of people making do with simpler controls. Just because you *can* take things very far at a very high price, doesn't mean you have to. The external tracking of the head is going to be baked into the headset cost (and not that expensive, as Kinect has shown) Headphones are straightforward as is positional audio in the headphone situation. Beyond eyewear and headphones, things get optional pretty fast. Wiimote-grade tracking for hands I certainly see as a big value add, but things start falling off real fast beyond that (the treadmill I'm skeptical would do anything to pull me that much more in as I think it would still feel very very off, but would wear me out greatly).