that have taken bear and deer in the continental U.S.

Old hunters mostly used a few calibers. Who buys fifteen calibers and uses rhem ? Most hunters try a few. And those are their favorites. The rifles worked.

Decades ago, .270 got a reputation for a western U.S. cartridge by writer Jack O'Connor. I never did think of it as an eastern cartridge after that.
One caliber became an unfavorable to me. An acquaintance shot a deer with one caliber; the deer ran over the hill and was downed by a hunter with a 30-30.
I could never shake that memory and never bought that caliber.
I never did find out how bad a shot he was.

And that's one story how we come to liking certain calibers.