In America, the common reason for owning a gun is to "protect my family". But as the fictional world of "The Walking Dead" shows that when the shit hit the fan, you will need a lot more than just guns, guns and more guns. The are many different scenarios where you will need to bring more than just a gun to the fight.
The people of the walking dead have a lot more to fear than the zombies. Even when they have plenty of guns and ammo an even " Build the wall". They still need to feed there families and friends. Inside the wall, there is a community of people with each with there own skills. This community grows there own food, has a doctor as well as other skills. If you had just guns and ammo. You would not last long in SHTF event.
As the saying goes there is strength in numbers. This is called social capital. In this era of social media, there is a real lack of a sense of community and more of us vs them way of thinking.