Worry less about caliber, worry more about bullet construction and what style of hunting you do. If you are a dark timber cruiser, a heavier deep penetrating caliber/ bullet is a better bet. If you are a ridge sitter then you might want to be set up for longer range equipment.
I do both, I've killed some 30+ elk over the years. My two favorite elk rounds are a .30-06 with a 180gr TSX or a .375 with a 270 gr TSX. My longest elk kill to date was @ 447 yards with the .375H&H. I have found no difference in knock down or killing power between a .30-06 or any of the .300 mags. The only thing you gain with .300 mag of any kind over an 06 is about 50 to 75 yards increased max point blank range. The last elk I killed with a .30-06 was at 233 yards with a 180gr TSX. The bullet hit just behind the on shoulder blew through the heart and lungs and exited the off shoulder after breaking the big bone where the blade and the long bone come together.
My favorite way to hunt elk is up close and personal in thick, dark, timber. That is where something with some penetration comes in real handy, thus the .375H&H. These Best of the West guys with their 1,000 yard plus shots on camera do nothing for me. To each their own, and I get my max enjoyment when up close a personal with elk.
I like a rifle,scope, and bullet combo that allows me choices in how I hunt. I like to be able to cruise timber and handle off angle shots or make that 300+ yard shot when it is presented. There is no right or wrong answer but the things I like in an elk rifle are;
Ease of carry
Fast handling
Low mounted low power variable scope
Short and handy
A well constructed bullet that won't break up or stop on heavy bone
A caliber and bullet weight combo that will penetrate to the vitals from all angles
Flat enough trajectory and be well practiced enough to make shots out to 400ish yards
The man matters far more than the machine. The bullet matters more than the case. I don't understand why every greenhorn in elk country automatically assumes that every shot oportunity is going to be at 500+ yards. I just don't take those shots and it hasn't slowed down my success rate one tiny little bit. If the wind is blowing my shot envelope shrinks considerably below 400 yards BTW. Environmental conditions matter.