It's part of a rarely-discussed issue with beyond-visual range (BVR) missiles. For all the hype about technology, they have a horrifically low kill rate against live and aware target. If you look at stats against maneuvering opponents actually beyond visual range, ones with the senors to detect the radar-guided missile approaching, the kill rate is on the order of 15%. Doing the math, the fancy new fighters don't have the missile capacity to confidently down any BVR target, hence the need for a "truck".