An alternative hypothesis that might explain the evidence: Ideas like natural selection, atomism and intelligence explosion are independently invented a great many times, but the apparent scarcity comes from the factors that lead to them being recorded or spread not being in place. For example Darwin was nowhere near the first to talk about natural selection, but the combination of a critical mass of scientific evidence and a receptive cultural climate made it possible to spread it. Conversely, Democritus may have had the idea of an intelligence explosion but there was no reason for it to be recorded and passed down.
An alternative hypothesis that might explain the evidence: Ideas like natural selection, atomism and intelligence explosion are independently invented a great many times, but the apparent scarcity comes from the factors that lead to them being recorded or spread not being in place. For example Darwin was nowhere near the first to talk about natural selection, but the combination of a critical mass of scientific evidence and a receptive cultural climate made it possible to spread it. Conversely, Democritus may have had the idea of an intelligence explosion but there was no reason for it to be recorded and passed down.