When I was a teenager and I first started dove hunting in the late '60s, 12 gauge shotgun shells could be bought for about $2.75 or thereabout for a box of 25.
I ran that through the inflation calculator and it indicates that similar shotshells should cost $16/box today. They actually cost less than half that, so this commodity is actually more affordable today than back then. It also explains why almost nobody reloads shotshells anymore.
I bought a Lee handloader back then just so I could afford to shoot that shotgun.
A lot of things become more affordable simply because we invent less labor intensive methods of manufacturing them. I imagine that in the 1800's, there was a lot more skilled hand labor involved in gun making than today with modern CNC tools and so forth.