Fred Flintstone would put his cat out for the night. This scene alone has convinced generations of Americans that releasing a car into the neighborhood part time is both the normal and maybe even preferred way to things. If I so much as suggest otherwise, I get dismissed as a lone who has no idea what a cat is much less how to own one. Cat hoarding inside is an equal problem to releasing sem-feral cats outside, but at least the animal hoarders have mostly come to understand that this is problematic behavior.
Not a month goes by when somebody doesn't ask me if I would like to adopt kitten. They doesn't happen because my community has a two animal limit; I could not even keep three goldfish in my house. My wife's cat and our houseguest's cat bring us right up to that limit. I allow the cats, but I trim their claws myself once a week.
The best solution is to spay and neuter the majority of cats in the country and get the population under control. Unfortunately, spaying is very very expensive to do in the U.S. and far beyond the means of most people with multiple cats. Until somebody invents a cheaper process for feline birth control, this is just a problem we have to live with.