Yes, it's definitely not running over CAN as CAN doesn't provide enough bandwidth for cameras. Usually the cameras are connected using LVDS or in newer cars, ethernet.
I don't know why not; IIRC FireWire was LVDS (4+m), and LVDS doesn't specify ("care about") distance, just loss between driver and receiver. I vaguely recall lossless transmissions between 10-30m, which is more than enough for a vehicle.