A 9mm carbine is great for people who only need to defend their house and the immediate vicinity around it. The Army issued many of them to drivers, and other branches issued them for other close quarters work. Some people can grab a carbine in the middle of the night for defense during a break-in. The pointing characteristics of most carbines are good. Other people need something lighter to lift and point, like a pistol.
Many rural people should have some kind of rifle, though, especially those with large, open areas next to their houses.
I’m not in a rural area, but if the SHTF being able to hunt would be useful. My concern with rifles though is the availability of ammo right now. I could buy an AR or something else but be stuck without enough ammo to train or use. I am good with 9mm. Maybe the supply issue will ease up, but I kinda doubt it.