You seem to be missing the point - you can't go from having the brain of a sea cucumber to doing calculus in one fell swoop. The rate of production of technological species will be dependent on the rate of production of *nearly* technological species.
At the moment. But do remember that to start with, Modern Humans had other tool-using competition. The Neanderthal or the Denisovans could well have been the ones who made it, instead of us. It is quite possible that Earth produces several hominid species that fit the bill, but only one survived intact to the present day.
Oh, and here's one for you - the signs of civilization on the surface of a tectonically active planet should last about 3 million years, after which, they will have either been eroded or buried away. If there were species of dinosaurs that made it up to stone-age tech, we likely would never know. Speculative, but a point worth making - our window for recognizing when there has been intelligence is large on human terms, but limited in geological ones.