That's been my experience almost exactly.
To me, it's simply a proportional proposition: The bigger and tougher the animals are that you want to hunt, the more cartridge and the more bullet you need.
I don't insist on making a 270 Win. do the work that is best done by a 338 Win. Mag. I'd rather hunt deer with a 270, and I'd rather hunt elk with a 338, pure and simple.
When in doubt, I take a 300 Win. Mag loaded with premium 180s. It shoots flat enough for any realistic hunting situation, and based on rather extensive personal experience it, that cartridge good for 98% of the world's big game.
So where's the complication, anyway?
AD