The 308 was NOT adopted because it "Did everything the 06 did " it was adopted because it saved powder(money) and was still enough to kill a man(average weight at time the 308 was adopted 150ish probably), NOT the same thing. See what the reloading manual says about 220 gr bullets in the 308 vs the 06. Some of mine only go up to 190s for the 308. All this doesnt mean the 308 isnt a good caliber.
as to the original post. I dont think that the 308 will ever go under in the east or south where shots generally arent as long and the animals are smaller(meaning deer instead of elk). under 200yds the 308 is a great killer, and if the shooter knows his gun, farther.