Gosh Scootrd, for me, I would just file this under the category of "who cares?"
Though its been a long long time since I read his book, the Hunting Rifle, my recollection is that he heaped incredible praise upon the .30-06 in that work.
And, when you come right down to it, although the .270 is an exception caliber, it's limitation to 150 bullets does not make it the best all-around hunting rifle by any means. It is simply one of many calibers, including the .30-06, .308, and .280, that can handle 95% of all big game if you throroughly understand your rifle and caliber, and utilize proper bullets and exact bullet placement. (My understanding is that the .270 is actually a .278 caliber, so how exactly is it "superior" to the .280 Remington?)
I think that what O'Connor did was to be one of the first people to thoroughly research and master the .270 in all respects, understanding its power and its limitations, and to use it accordingly. Unfortunately, 95% of all of the people who use a .270 are not masters of anything, and simply rely on its reputation (as opposed to their marksmanship) to try to kill very large game, often with bad results.
Just my thoughts,
Mannyrock