I think the 30-06 is the cartridge that meets all of our subjective wants and our objective needs, without many of the negative attributes that other cartridges might bring. Our hunting community is dead set that it takes 1,000ft.lbs. at impact to kill deer, so we ALL tend to favor 'over-kill cartridges' like the 30-06, putting us into some interesting considerations for performance at both ends of the rifle.
I'm not saying that I agree with or believe there to be any merit to ANY of these, but I believe that these could be very common responses when considering any of these other popular cartridges over a 30-06, based on the mindset of our sporting culture:
- 243win - well by golly, that's just under-sized, the 30-06 hits harder
- 30-30win - man, that ol' levergun doesn't shoot flat enough
- 300win mag - doesn't kill the deer any more dead, just kicks a lot harder, and who needs extra recoil? Also burns more powder!
- 7mm mag - same problems as the 300 mag, too much recoil, but worse, 'cuz it's metric!!!
- 308win - it's like a ".30-06 Light"... Light beer is for women and liberals
- 270win/25-06 - doesn't have the bullet weight to kill the big stuff, it's like a 30-06 but for coyotes or speed goats
A guy could go on and on... Basically, I read the ESTABLISHED shooting culture that 1) anything smaller isn't as good because it's smaller, 2) anything larger isn't as good because it recoils harder.
I even find myself being a bit hypocritical in this sense. I've instructed a lot of new shooters, and mentored a lot of new gun buyers - if you ask me what cartridge to get as a first deer rifle, I recommend something like a 7mm-08, a 25-06, 243, etc. But when I go to my safe each season, if I can't make up my mind on what "better rifle" to take afield, my default always goes back to my ol' aught six.
Side note - I say all of that and I can't help but think of the "new shooting culture" that is evolving around us. New gun owners that are more influenced by youtube fads than tradition, and that weight rumors and speculation from mall ninjas more heavily than tried and true experiences in the field. I find myself confused to live in a sporting world where the 300 blackout has this much traction, but the 308 Marlin was flash in the pan. These shooters are the kind that would NOT buy a .30-06, simply because it's not present in Modern Warfare video games, or wouldn't buy it BECAUSE IT'S A PROVEN HISTORICAL CARTRIDGE.
I don't necessarily agree, however, that the .30-06 is "great at everything, but not great at anything." I find that the 30-06 is quite likely the ideal cartridge for elk sized game. Not too much punishment on the shoulder, but plenty of bullet weight to do all the killing you want at any range that you're able to connect. I would say that my opinion is that the .30-06 really is a GREAT elk rifle. Even though most of us carry one for deer, for which the ol' Springfield is drastically over-powered. It'll kill anything you hit well with it, but in terms of ideal balance of killing potential and recoil, it's too much for coyotes through deer, and too little for bear through bison.