Well, Idaho aint to much different from Oregon...
I've packed more then my fair share of elk out of the bottom of canyons. Not from them running down there, but from them dropping with shoulder shots, and them tumbling down all the way to the bottom. Come to think of it, I've helped track and pack elk that were shot poorly with 7 RM and 300 WM's, it aint no different then a bad shot with a .270...They werne't any of my elk, but when your hunting camp is 10+ strong, you sometimes got your work cut out for you when you start dropping elk in the canyons. And since I"m 21, Mr. Young buck according to all you old geezers, I have to pack your elk out of the bottom every year. Trust me, I know, you dont have to tell me. The elk are no different packing out when shot with a 270 vs a 300 Mag...
I've seen .270's kill elk since I was in hunting camp. Its all my dad used for 10 years and he never lost an elk?? Seen several others come to camp with .270's and collect there elk. I've seen them pushed to there outer limits, as I have with all calibers. A lot of shooting is done from cross canyon which is 300-500 yards. I will say a .270 w/a good 150g bullet at 2900fps+ is more then adequate for elk to 600 yards, providing you put the bullet where it needs to go. A 30-06/180g bullet isn't going to do any better, or worse for that matter, but I'll personally take a .270.
I'll agree with you though that if you can handle a magnum, and shoot it as well or better, by all means use it!! I have shot all my elk with magnums 7 RM, 300 WM, 300 RUM, but I know there not neccesary...They will kill elk well past 600 yards when put in the right spot...
FYI, I dont think elk require 1500 ft lbs to get have clean kills. I would think more along the lines of 1,000 ft lbs is more like it at the minimum end...To each his own..