I think part of the problem with "the perfect" elk rifle is the fact that elk live in such different terrain.
If I had to always shoot elk in timber I would pack on of two rifles, the first would be a 338 win type shooting a TTSX in a 8 lb ish package with a low power variable scope like a 2.5-10 NXS, the second would be a Marlin 45-70 loaded with 300gr hollow points pushed hard, maybe an optic maybe just open sights.
The stuff I hunt the most is very broken timber and sage brush, by far the most popular amongst guys I know is the 270's a few 243's and a few 30cals only one 7mm, commonly know as the 7 meat mangler
Typical elk shooting is from point blank to the 500yrd range, and you always have the possibility for a deer also, generally you load a bonded bullet or TSX or judiciously a Berger, something that won't be to bad on deer but reach the far side on and elk.
For the long range from canyon to canyon or out in the field bottoms all the guys I know that do it hunt with 338 RUM min and you see quite a few Cheytac size stuff. Bullet choice for every one I know is the 300gr SMK with a couple of Rocky MT bullet shooters and now the 300gr Berger is hot!
Bullets have a great influence on chamberings, I do know one guy that shoots a 338 and swears up and down elk are bullet eating monsters but I look at what he shoots out of it and it is a way to heavy Partition going way to slow, ya elk will eat slow moving, barely expanding bullet put behind the shoulder and I've seen quite a few take a mag full of them and move out. I've seen the other end of the spectrum where a guy will swear he needs a bigger cal but he's shooting elk in the shoulder with a 140 gr Ballistic tip in his 7mag, way to fragile of a bullet going way to fast for where they shoot them. At least the elk shot with a 338 will be recoverable, if you have no penetration and just blow up a front shoulder you odds are slim of recovery.
Good bullets shot with in there functional range and placed in the appropriate location for that bullet is all it take to kill elk like a rock star!!