Food, especially fresh food, used to be a lot more expensive when adjusting for inflation. A canned chicken like this doesn’t look super appetizing right out of the can, but it probably tasted OK after you shredded it and put it in a casserole. And it was significantly cheaper than buying a fresh whole roasted chicken, assuming you lived somewhere that fresh whole roasted chickens were even readily available. Food like this became particularly popular during the great depression, and stuck around for decades afterwards.
Nowadays, between industrialized farming, highly optimized supply chains, and a buttload of government subsidy, fresh food is comparatively cheap. You can get a whole roasted chicken right off the spit for $5-10 at just about any grocery store. So for most people the value proposition of a $3 canned chicken isn’t really there anymore, especially if you don’t have an enormous baby-boom-era sized family to feed.