G forces? There is no benefit to aircraft that can pull more than 9G, which is already sustainable by the human body. Oxygen systems don't take up that much space. Yes, ejection seats are extremely expensive, but you cannot build a robot to make the same decisions a combat pilot makes and in the time a human pilot makes them. Needing to pee? Its called a piddle pack, and its called bringing food to eat. Those do not decrease loiter time at all.
You would think support is the main focus at usafa nowadays though. Just look at the commercials on tv, everything is about being anything but a pilot, let alone a combat pilot.