That's the illusion I think. Because you only "look" at the center spot of your vision, obviously. If you're standing in a dull room with a window to a bright exterior, and looking at an object in it, you can't "look" out the window, without it effectively being another picture/viewpoint. It's in the corner of your eye. Granted the eye has a much higher range than any camera sensor or film, but the effect it still there.
If you could take a screenshot of your vision looking at something in this room, and then look directly at where the window would have been in the corner of your eye, it would be brighter/duller respectively.
When you look at a HDR photograph, it effectively emulates a still scene which you can focus at different points of and get the same effect as if you were doing just that when you're there. That's why it "looks", in a way more realistic, but it's not exactly how the eye works.
HDR in game doesn't try to replicate HDR photography in any way shape or form. It tries to do exactly the opposite. If you get a none HDR game like Unreal Tournament, and stand in a dull room with a window to a bright outside environment, and take a screenshot, the view out the window, and the detail inside this room will all have good contrast, just like a HDR photograph.
If you do the same thing in a HDR game like Half Life 2: Lost Coast tech demo, you'll get the same effect as when you take a picture with a normal camera. While you're standing, and focusing on objects inside the room the view out the window (which is effectively "out the corner of your eye") will be just a big white overexposed area. If you focus outside the window, you'll see detail, and things inside will all go dull.
So if you want a game to emulate what HDR photography does, then all games currently do. If you want a game to respond how normal cameras, and to a degree how the eye does, you need a HDR game.
Here we go, a perfect example!
The right hand side of this picture is what a normal camera would see as it has some overexposure "bleed" and underexposure, and the left hand side is what you'd get if you took multiple exposure levels and combined them, aka a HDR photograph. Yet, in the game, they are the opposite! So once again, a HDR photograph, is nothing like what HDR in video games tries to emulate. The effect HDR photographs are aiming for has always existed in computer games from day 1.