Your first example is boredom. It entertains you to own these relics, antiques, and the like. No harm in it at all. Amuse yourself however you like. All hobbies fall under boredom, no?
Fair enough. Although I would say intrigue could be a motivator absent of boredom.
Second example is fear. Worried that there wouldn't be enough food, you sought to hunt and help provide. Would you say that's still an issue for a plurality of families in the U.S. at this point? That seems like a situation that society has mostly outgrown through food production and distribution.
I disagree, we weren't afraid of not eating, my father always provided. However its hard to feed a family of 7 steaks on a very modest single income. Hunting allowed my family to eat organic steaks, burgers, and brats that we otherwise would not have been able to afford. I remember my grandpa giving my dad a dehydrator and smoker when I was really young, venison jerky tasted a lot better than apple or cucumber slices for school snacks. How much would it cost to send jerky with five children as a school snack? I still have that same rifle today and it has more that paid for itself. Since then I have acquired more firearms, you would probably say I bought them out of boredom(as you've made it clear hobbies = bored

), handgun to shoot leagues, shotguns for trap league and grouse hunting, etc.
I'll will say that I bought my carry piece out of cautiousness. If fear is a motivator, why not caution? I don't carry all the time, but if I'm going to buy something off craigslist and am carrying a decent amount of cash, I'll carry my gun too. You may say that is fear, but if I was afraid of something happening I would buy the item I'm looking to acquire from another seller. I contend that it's caution, not fear.
The third example is certainly an oddball, but the guy either wanted the job very much, or didn't want to bother trying to find one that didn't require such a purchase. What would you call that, at its core? What would you say was compelling him in that scenario?
I haven't talked with him in years, so it would be hard to say. I do remember he was going to school for criminal justice, perhaps he wanted a job that would align him better for future career aspirations.
And your last example I've already addressed. Those who are protecting livestock/land don't fall into either. Sorry you seemed to come in only at this point and think I'm just another pinhead, but I'm not. I'm also not actively against people owning guns. I'm not a gun-grabber of any kind. I just like people to have the deepest possible understanding of what motivates them to do the things they do. It's philosophical.
I wasn't assuming anything of your intellect, just wanted to give examples of motivators I knew of; seeing as no one else had given any specifics.