I'd have to see these examples and proof they weren't just another build of the actual games.
I believe I know what Last of Us demo you're referring to (and why you're referring to it) and that looked like the game to me. To be clear, I wasn't saying flat out it doesn not happen. I am very skeptical it has in this instance.
Here ya go, Halo 2 E3 2003
Bioshock Infinite 2010
And then 2011
Edit: Lol, I'm not sure how I can prove it since I don't want to go digging for interviews from several years ago, but in Bungie interviews they admit that the proclaimed in game footage they showed off wasn't going to be possible on the xbox when it released.