At this point, photorealism isn't so much a question of hardware limitations as one of scene complexity and interactivity. If you have a simple enough subject

At this point, photorealism isn't so much a question of hardware limitations as one of scene complexity and interactivity. If you have a simple enough subject to start with, and bake enough lighting and shadow mapping into the textures, you can make a photorealistic scene on even previous-generation console hardware. Once you start adding more objects, and allowing more things to move, you start needing to calculate more in real time, and you need more processing and rendering power. A room with a table and a teapot could probably be made photorealistic on a PS3, even at 90 FPS. A densely populated street with moving cars and pedestrians, however, would have to be fairly visually abstracted to hit that target even on a PS4.