Whilst nothing you say here is wrong, humans have a tendency to want more things than machines. A place to live (perhaps a mansion with its own pool), transportation (maybe a private jet or a million dollar supercar) and other general recreation (such as a datacenter full of GPU’s hallucinating cartoons of scantily clad women). So really, a human is pretty energy intensive when you think about it, compared to their rather low number of working hours (eesh, sleep takes so much time).