Over the decades, my mother has fostered approximately 20 or so cats born in the neighborhood outside to strays. She will either bring them to the AWA or a no-kill shelter for adoption, find them a home personally, or adopt them into the household. To this day, all the cats my parents have owned were brought in from the wild and socialized.
Ignorant owners are solely the cause of decades of time and money invested in that endeavor. Their house is near a major state route and there are a shit ton of drop-offs. And the worst part is, nobody else in the neighborhood gives a fuck. It has been only through the efforts of my mother that the cat population has been kept in control in the neighborhood where I grew up.