We don't have any neighbor cat trouble. I live on the prairie and hear coyotes most nights. That might have something to do with it, I'm sure the cats can't out compete a pack of dogs.
Did have a litter of kittens dumped in our driveway two years ago. We saved them to go to the shelter. After that who knows.
I'm not much for interfering with Ms. Nature, other than our bird feeder in the window. She's a harsh mistress, who knows her territory and her staff.