It was probably pretty good a long time ago before traps and poisons and an exterminator you could call up. I can honestly say that I haven't seen a stray cat in years. Do people even let them out anymore?
We have three cats that are allowed outside. One of them has cleared our yard and our neighbors' yards of chipmunks as well as putting a dent in the field mouse population in the field behind our property. He also has caught and killed two rabbits, four squirrels, numerous lizards, and many birds. The other two have yet to match his skills but one of them also just started being let out in the last two weeks so she's still in exploration mode but her sister has been going out for a couple months and has a few kills.
I see them but it really depends on the neighborhood. A poor neighborhood with a lot of critters in the alley would have some, a really tight upper class neighborhood with fewer plants, not as much.
My parents had 4 strays living under their deck for years until the last one died 3 years ago. My dad is not a cat person, but he haaaaates chipmunks so he was happy to have them. They have one stray that wanders their neighborhood now, which they oddly don't like but I adore. Sure he hisses and swats, but he's a sweety when you get past all of that.
I wonder what the rate of killing rats and mice were between cats and human dockworkers. Cats were probably worth their weight in gold