Until humans are replaced as a species by machine intelligence, humans will be the best and most efficient artificial intelligence. It takes the same amount of calories to operate a 60 light bulb as it does to run a human body for a day. Humans are incredibly efficient at turning calories into intelligence. Even when machine intelligence surpasses us in total intelligence, humans will still probably be more efficient. I think this is why for most of human history slavery was a accepted practice. I think we are in a short period without slavery (although arguments can be made about wage slavery), and I think it will return again at large scale. This would happen if energy became more scarce either through us using up resources or regulating heavily the use of resources we have. Now that I think about it more, maybe slavery won’t make a comeback because energy is just too prolific. I do think that human intelligence will continue to dominate until true AI comes.