I don't think you understand the process of making a good 3D product. You can't just throw in 3D afterwards, or have a "stock" 3D button experience if the games not specifically made for 3D.
Ever seen a movie that wasn't originally supposed to be made into 3D and then they added it after? Alice in Wonderland, anyone?
Now, compare that to how Avatar looks. Alice in Wonderland wasn't filmed for 3D, it was added after editing. Avatar was filmed for 3D, and that was the plan and intention from the beginning.
Same thing with video games. If you have a game that wasn't meant to be 3D, it's going to look awful if you add 3D to it. How does the card know what to make 3D, what to pop out, what to shade, etc? It doesn't, and it looks awful.
It is not the same thing. You don't need the processes of making a good 3D stereoscopic movie in a game. By definition, games are already 3D. 3D depth data is present in games, known as depthbuffer or z buffer. Besides in games, full position data is available too. So that's how your video card knows how to make it 3D and shade it correctly. The pop-outs, now they are different. Normally they shouldn't pop-out of screen like in Avatar example where screen is like a window. But it is possible to make things pop-out of screen too. That may need some additional work for developers(adjusting depth values of custom elements to make them pop
out of screen), but it won't look awful without it, it will look like Avatar.
In AiW, they create fake depth layers to give 3D, I think. Their digital parts, which occupies %60 of screen have correct depth values because of being digital. It is only the actors ruining it. Also most of the actors are just faces, bodies digital. So I think Alice might have worked better than let's say Clash of Titans. Unfortunately I didn't see both, so mine is just an assumption. I will guess only creature effects looked 3D in Clash of Titans.
You need only hardware and driver support. Game developers must just make sure the hud, sky boxes, particle layers don't ruin the vision(which should come by default). So it is a choice and 3D will only do good in game be it a 3D puzzle to be solved or high pace action with particles flying all around after an explosion or an arrow coming to you in TES game. It is about immersion. It can work. Again it is user's choice to switch it on. It has no cost to a player who wants to play 2D. But:
@miltos33,
yes. You have to double everything. Hopefully it will become more accessible in the future.