This is a point everyone makes, but it hasn't been proven anywhere. Progress in AI as a field has always been a cycle of hype and cool-down.
Edit (reply to below). Talk about self-bootstrapping AIs, etc. is just speculation.
Just as one discovery enables many, human-level AI that can do its own AI research could superlinearly bootstrap its intelligence. AI safety addresses the risk of bootstrapped superintelligence indifferent to humans.
Of course, that assumes the return-on-investment curve for "bootstrapping its own intelligence" is linear or superlinear. If it's logarithmic or something other than "intelligence" (which is a word loaded with magical thinking if there ever was one!) is the limiting factor on reasoning, no go.