Progression of tech tree. The small battery accumulator requirement for the ATV is a late requirement. By the time I get to that point I usually have enough points to go right past the ATV and right to the Truck making the buildable ATV pointless (except for fun) as I just go straight from the starter ATV to the Truck until I get to the Rover. If I could build my own ATV sooner, then I would use that until I could get to the Truck. So, I guess the point is the progression feels really out of order to unlock what is intended to be an earlier access point, that is locked behind a futher along progression gate.