A substantial amount of people were farmers/lived close to nature though. It's just... pet food wasn't a thing, in the best case you might toss some meat leftovers (though I suppose those would mostly go to the dogs and pigs). Cats roamed and are pretty capable of keeping themselves fed when they're healthy. I doubt it's as much a question of people keeping cats than cats staying around sources of easy food (vermin)/warmth/scritches behind their ears. You didn't need to be able to afford cats, they can take care of themselves.

Same as with your pet cat. If it's a freeroam, it'll hunt anyway regardless if you feed it or not. My previous cat was semi-freeroam (couldn't get out the connected backyards) and at one point he took the neighbours' rabbits home. Over a 3 meter/10 foot wall. Mind you, he was well-fed and lacked for nothing. My current is indoors only, she attacks anything on 4 legs on sight. Including the neighbour's German Shepherd. Hunting instinct is big in cats and never went out of them.