What happened to voxels?

Forgive me if this is massively ignorant, but: I recall reading in Edge years ago that voxels (individual 3d points) would replace polygons as the main basis of game graphics soon. The argument was that when hardware gets so powerful that the polygons are frequently smaller than on-screen pixels, it's a waste of computing power to use them, each requiring multiple points, and voxels would be more efficient. We're surely at the point now that polygons are smaller than pixels, but voxels in games still seem fairly rare. Does anyone know why?