A quick search says there’s 2,000 chimps in captivity in the US in various hands, wouldn’t surprise me if there were a few hundred more ‘off the books’. So up to a half dozen or so getting loose every year seems reasonable to me. And if they’re in a warmer area with plentiful food sources they’re in luck.
Here’s a red deer we had roaming our property, no idea where it came from or where it went, has a tag in it’s ear. Despite multiple black bear/mountain lion sightings on the place have never gotten a picture of one. But the passing red deer which is as rare as a hen’s tooth practically poses for the camera, probably still out there somewhere.