In a way, the demise of the dinosaurs is kind of like the fall of Rome (the 5th century one), in that the conditions created by the impact wiped out many of the dinosaurs, but birds survived and are only not considered (by some) to be dinosaurs because of our categorisation, in the same way that the fall of Rome which was completed by Germanic invaders left the Eastern Roman Empire to survive long after that, and despite denial from some, has direct descendance from the Roman Empire.