First, as wahoo pointed out in his post, shotguns don't come in nearly as many different chamberings as rifles, which is one reason rifle loonies like to fool with a lot of different rifles.
Second, since about WWII the upland bird hunting in the U.S. has been generally going downhill, both due to fewer birds and places to hunt them. In the meantime big game populations have generally increased, especially whitetails and elk.
You also can't brag about half-inch groups from shotguns!
“Montana seems to me to be what a small boy would think Texas is like from hearing Texans.” John Steinbeck
