I'm not sure how useful or relevant a point this is, but I was just thinking about this when I saw the comment: IQ is defined within the range of human ability, where an arbitrarily large IQ just means being the smartest human in an arbitrarily large human population. "IQ 1000" and "IQ 180" might both be close enough to the asymptote of the upper limit of natural human ability that the difference is indiscernible. Quantum probabilities of humans being born with really weird "superhuman" brain architectures notwithstanding, a truly superintelligent being might have a true IQ of "infinity" or "N/A", which sounds much less likely to stick to the expectations we have of human savants.