.300 Winchester is actually used and useful for those few hunters who honestly take critters at extended ranges; 500 yards and further.
.300 Winchester is actually used and useful for those hunters who hunt large, dangerous game in North America. Large bear, Moose, Caribou, and that category of critter that will eat one or just stomp on one.
.300 Winchester is actually coveted by those who prove their manhood by having one, spurred on by clever marketing.
I don't even pretend to shoot anything that far off. Even paper. I own a .375 Ruger, far superior in my thinking to any .308 caliber rifle for large game, dangerous or not. However, with every day it grows less likely I will hunt in Alaska and surely not Africa. So it may be just as smart to peddle it off in a year or two.