Re: Two things.
Games, yes. When done well.
Many years ago by modern time scales we had a nice sideline selling "virtual reality" gear. The killer demo was Quake at high res (1024x768 woohoo!) in stereo* with shutter glasses. Really freaked people out when they saw it. We spent most of an afternoon tweaking sync, frame rates, convergence and DOF to make it so. Mechwarrior (2?) was another good one. Tombraider was awful and Descent just made people motion sick.
The problem was that we set it up right and the customers didn't so 9 times out of 10 they weren't so impressed by their real world performance.
What you say tallies with my experience of live generated content. But most of what we are talking about here is recorded content. For this stereo is little more than a gimmick because it's viewed from a predefined angle, with a predefined field of view. The only really good stereoscopic video I've seen was from last years Tour de France (and I reckon I spotted the guys filming it with a pair of Canon 7Ds in the regular broadcasts) and frankly that had only novelty value.
To sum up: yes you are quite correct that stereoscopic video can be very effective. But it's only useful where the extra depth queuing is useful. Otherwise it's just novelty and novelty wears off.
Oh, and I really must go see if R-Factor supports stereo displays 'cause that combined with head tracking sounds awesome.
* Calling a spade a spade here - it's not 3D, it's steroscopic