American culture is specifically oriented toward preventing this kind of thing from happening. A feral cat is judged to be in need of a home. And there is a very widespread popular effort to say that you are doing something immoral if you don't spay your cat -- if a fertile cat did go feral, it might have children!
There’d be at least a couple hundred in any one block. Thousands at night.
Keeping someone captive and ending their ability to reproduce seems more like abuse than love.
But coyotes and maybe even wolves have become more common. Such that I remember people remarking about how a housecat wouldn't last long if left to roam. The predators may have increased due to other prey becoming more common as well, like turkeys.