The basic difference between guns and other stuff consumers buy is that guns do not wear out, like toasters, they are not consumed, like Pop Tarts. If you buy one and take reasonable care to keep it dry, the fucking thing will last for centuries.
This is a problem to a company selling guns. They need to turn the guy who has just one gun to defend himself with into a collector, who has a variety of guns to defend against bad people. One gun for burglars, another for kidnappers, another for prospective rapists, and a semi-automatic assault rifle should one be assaulted by Isis or Al Qaeda as the try to take over the PTA meeting.
Hunters might need a collection of weaponry: you would not have much to take to the taxidermist if you used your Grizzly Bear gun on a squirrel. But the self-styled Good Man with a Gun really needs just one gun.