While I'm hardly an authority on these matters; I believe highpower rifle competition used to be all .30-06. When they began using .308 Winchester, it began breaking all the '06 records. .30-06 is a fine cartridge, and I'm not trying to change your mind. Just wanted to point out that among serious, highpower competitors, the .308 is preferred over the .06.
That brings up a question: Is there something more accurate about a shorter powder column? Or does it have to do with a shorter, stiffer action? Or are neither significant?
I think it was a recent Rifle Shooter magazine that had an article on cartridge "efficiency". They related a bullet's kinetic energy for a given cartridge to the amount of powder used to achieve it. The .308 Win scored very high in efficiency. Increasing case capacity and adding more powder will increase kinetic energy, but there are diminishing returns. Doubling the powder doesn't double the bullets energy, so magnums aren't as "efficient". Of course, efficiency is just one measure of a bullets performance.