You need to look at the heavier bullets with better BCs to really start to see where they out shine the 25-06. Im not looking at 500yrds. Im looking at 800-1000yrds. Take the 30-06 and use a 208 Amax at 2750fps. Then look at the energy, and the wind drift. The wind drift is the most important factor. PS- im not a 30-06 lover. I dont have a 30-06, but I have a 25-06. Im just posting what I have seen.
drop drift vel energy
800 -162.4 -19.4 36.6 4.4 1798.3 1493.4 30-06 208amax @ 2750
drop drift vel energy
800 -139.9 - 16.7 44.5 5 .3 1767.7 797.8 25-06 115 berger @3100
This is @ 800 yrds. It only gets better from here.