Eventually, we might not be the best at that either. Imagine AI companions that can not only perfectly emulate human behaviour, but can produce simulations of empathy, compassion, humour, etc. perfectly tailored to an individual's psyche.

When we imagine intelligent AIs keeping humans as pets, we tend to do so in analogous terms to how we treat animals: E.g. in sparse, constrained environments, like cages and zoos. But those environments are designed with animal level intelligence and instincts in mind. AIs will probably design habitats intended to placate human instincts. And a big part of that will be keeping us psychologically happy, which will involve providing simulated companionship.