Ferrets have actually been domesticated for thousands for years - whereas arguably, the "domestic" cat is really only semi-domestic, because they were kept around for their hunting abilities so basically were rewarded for their natural instincts, and plus cats keep breeding with feral cats. But domestic ferrets would have a harder time because they haven't been "outdoor" pets for so long. A ferret who was fed live mice might retain some hunting skills, but a ferret on the streets just won't survive long without food or water, and plus, will be likely to approach humans. Additionally, ferrets are typically sold already neutered, because female ferrets can die if they go into heat and don't get pregnant, so it's unlikely they ferrets would breed and create colonies of wild ferrets. "Three hours" was perhaps hyperbole, but a ferret is way more likely to get eaten by something, run over by something, or just get dehydrated or starve within a few days than it is to figure out how to hunt, be successful at it, and find a water source.