I've never understood the firearms industry. My understanding is that a gun is basically good forever, unless you are the type of person who shoots a ridiculous number of rounds every week, or you don't maintain it. So where's the demand from? Is it from a growing US population which increases demand for firearms? Is it from an increasing penetration of firearms (ie, the percentage of households who have a gun)? Is it from increasing the number of firearms per owner-household? It really strikes me that this should be a pretty mature industry with not much demand.
Now, contrast that with the auto industry which I understand better. Cars wear out and need to be replaced. The number of drivers increases with population, and the number of cars per household has gone up.
So, is there anybody who knows about the firearms market who can shed some light on market prospects?
SJ
Greater penetration across demographics. The firearm industry is making a concerted effort to attract women and millennials to the sport as well as groups where gun ownership isn't traditionally part of their culture. Essentially, we're seeing a change in the industry from the older white male demographic that has historically enjoyed firearms to a more inclusive slice of the American population.
One gun is like one pair of shoes, you don't have just one. Gun owners love to show off their newest acquisition and even if it only gets 20 rounds through it all year it will be in their gun safe as part of their collection. Guns aren't terribly expensive and a day at the range with friends can be thought of like going golfing. Gun owners want to have a collection of "clubs" to take to the range with them and shoot as each is different. Between an increasing slice of the American population interested in shooting sports, active efforts by the industry to attract a more diverse demographic, and the easy availability of a wide range of firearms I think there's a case to be made for industry wide growth.
Another factor that helps is great liquidity in the used market for guns. As you mentioned, they don't wear out, especially given the use conditions the average American gun owner puts them through, and with proper maintenance a firearm can last several decades and hold its value relatively well. The advent of online platforms that allow for sales between users helps spur the purchase of more new firearms - it's easier to justify a new purchase if there's a healthy used market for the product one can sell it into with little depreciation. I also think there's a novelty factor to just owning different guns, they all shoot a little differently and gun owners want to have choices.
With that said, the industry has a vested interest in marketing to new users, if that starts to die out or shooting sports become less popular growth will slow down. Gun owners interested exclusively in home defense are a separate and much smaller subset of users and I think a lot of your points make sense with them in mind but users interested in shooting sports and to a lesser extent hunting will continue to buy new (or new to them used) firearms well in excess of their "needs" for hunting or sporting.