At present, with more and more hand flying being discouraged, it is becoming harder to demonstrate statistically that a good pilot using their brains can indeed give you a fuel cost advantage over automation. Catch 22 as Yossarian said!
Believe it or not there are airlines that are real LNVA/VNAV sticklers for conformity, but they still have monthly fuel burn league tables. How does that work? You plug in at 1000' and plug out at 1000'. You have no influence, but just fly the route with the computer. Ripping visuals are discouraged so the fuel burn is not under your control. What is the point of league tables. Beats me.