>>339198I think you are ignoring an important fact: mammals were also evolving all that time, and the best they could produce was essentially a tree shrew. At the time of the KT-extinction, it was the dinosaurs, not the mammals, that were at the peak of the intellectual molehill. Only after 65 million years of climatic turmoil and continent drift unlike anything seen during the Mesozoic driving evolution at an impressive speed, did our kind finally ascend to true sapience. But what of the dinosaurs? Well, if you have been reading the science news lately, you'll know that the species with the closest cognitive capabilities to man is in fact an a highly evolved maniraptoran dinosaur: an avian (image highly related).
To argue that dinosaurs could not evolve sapience because they had not done so before the KT, is essentially arguing that they should not be able to evolve it afterwards. Yet both corvids and psittacids are both among the closest contenders to the most intellectually advanced clade on the planet.
Evolution has no goal, that much is true. While it often leads to complexity, it need not do so if an alternative solution can be tapped. But we have seen that evolution leads in a consistent way to the same kinds of solutions to the same kinds of problems. We know this as convergence. Within the last 65 million years the solutions have more and more often involved hyper-advanced brains combined with tool use. It is no accident of nature that humans are here now. If it wasn't us, it would be some other species a million or five million or ten million years from now. With enough time, with the right circumstances, anything not only can but WILL happen.