It seems to me from personal experience and from the experience of trusted friends with regards to hunting and shooting that the cartridges that got their start one hundred (100) plus years ago are all a person needs to successfully hunt North America.
With the bullets available today, including factory loaded cartridges, that for a hand loader the sky is the limit.
There is no mechanical, or more accurately ballistic, reason why even any of the cartridges I listed in this title cannot successfully take the larger deer (elk & moose) out to and beyond 300 yards. It comes down to knowing your equipment and your shooting skills. Though I myself prefer to shoot game closer because being part uhhhh crippled and part lazy, or a conserver of energy :) for the PC folks, I just don't want to walk any further than I need to. And then drag or carry my game back to where I made the shot or even farther back to my vehicle.
Sure for Brown and or Grizzly Bear it would be better to be closer and go heavy for caliber. But still these grand old cartridges can still and are still doing it.
Am I advocating that we or other hunters/shooters should just stick with these and turn our backs on newer cartridges? No not at all. I am a great fan of the 6.5 Rem Mag, the 7mm Rem Mag, 300 Win Mag, 7 & 300 WSM's, the 308 Win, 243 Win, 223 Rem 30-30, 260 Rem, 444 Marlin, 25-06 and so forth.
Variety is good. Bullets, rifles, handguns, optics, variety is very good.
No real point to this writing other than to write or speak the obvious as sometimes the very obvious is pretty hard to see.
Like what you use. Know how to use what you have. And enjoy it all including the experience you/we get along the way.