Actually that is true. 2D games can look very good because they are based off os flat images and solid textures. As a result all you have to do is draw pictures and we know there are many people capable of photo-real images.
3D on the other hand is warping that photo-real image around polygons. This can be very dificult at times depending on the geometry.
Of the games I have seen comming up I think Assisins creeed By UBISOFT is one of the most impressive and look forward to playing it. The characters and animations look almost real thanks to realistics physics and automated animations. Also it is being presented in trailers as though it where a movie and it can be hard to tell that it is not at times.