"The 30-06 shoots the same bullets 100-150 fps faster with about 25% more recoil in rifles that are slightly longer and usually a few oz heavier. In practical terms a 308 does exactly the same thing a 30-06 does about 50 yards closer."
That may not be necessarily accurate.
A few years back I did a limited test of Winchester 180 gr. Power Points in two .308 rifles and three 30-06's. The .308's had 18.5" and 22" barreled and the 30-06 22",24" and 26" barrels. Big W claimed 2600 FPS for the .308 and 2700 FPS for the 30-06.
Average velocity for the 18.5" rifle (Ruger RSI) was 2450 FPS, the 22" M70 2610 FPS. Average velocities from the various barrel length 06 rifles, 22", 2620 FPS.
24" was 2655 FPS average and the only one coming close to advertised speed was the 26" Ruger #1.
Further playing around that same M70 .308 delivers 2310 FPS chronographed with the 220 gr. Sierra round nose bullet.
AFAIK, only Remington sells an 06 load with 220 gr. bullet at an advertised 2400 FPS. I wonder is that load isn't also using cheated velocity in their advertising? I know apples and oranges for that last comparison but is it really considering that AFAIK no one has ever commercially loaded a 220 bullet in the .308.
I'll also admit that the 30-06 can be handloaded to a substantially hotter level as factory ammo isn't loaded to it's full potential. The original intent was testing with rifles with 22" barrels. The 18.5" and 24 and 26" barrels were run as an interesting aside to the original experiment. Temps at the time were in the mid 80's to lower 90's that afternoon. I fact, I was somewhat surprised that the .308 ammo came as close to advertised speed as it did.
To answer the OP"s original question, apparently in factory guise they might as well be considered equals. In handload though the 30-06 will win every time. The .308 is loaded to probably the highest safe level SAAMI will allow so not much room for improvement. The 30-06 due to some weaker rifles from it's past is not loaded to the same pressure level as the .308 so can be improved by judicious handloading. Naturally, YMMV.
Paul B.