3DS viewing angle - room for improvement?

[OneTwoThree]

I've never played the 3DS for longer than a few minutes, but what always annoys me is the tiny sweet spot for the 3D effect. A common complaint, I know. However I was wondering: Is there even a possibility that Nintendo could improve on that for 3DSlite, or is this effect unavoidable due to physics? Like, the distance between the human eyes? 

Some time ago I had read about an experimental technology that works with moving parallax barriers and eye tracking. But I'm pretty sure this is far out of reach for the 3DS' price point. 

Any ideas or rumors?

 

EDIT: Found something, but it sounds like distant future:

http://web.mit.edu/newsoffice/2011/glasses-free-3d-0504.html