In an early episode of the original Star Trek, aliens put Kirk on a rugged planet to duel with the captain of a rival Gorn ship. Kirk wins as the dinosaur-like Gorn was intelligent but really slow.
On Earth, dinosaurs never became intelligent. Arising 240 million years ago, they survived some 175 million years and for 135 million of those were the dominant land animal. By the time they became extinct, dinosaurs had perfected two ways of living: eating plants or eating each other. The plant eaters were excellent at converting plant matter into animal bulk and could grow very large. The carnivores were very good at using tooth and claw to eat the vegetarians. Some carnivores – such as the raptors – may have hunted in pacts and perhaps had some wolf-like intelligence. But in general, brain power doesn’t seem to have been on the dinosaurs’ primary evolutionary path.
Mammals arose just 10-15 million years after the dinosaurs. But for most of their first 160 million years, they lived underfoot as squirrel-sized, nocturnal plant eaters and insectivores. For this life style, relatively larger brains gave an evolutionary advantage. So under the feet of the dinosaurs, mammals got smart. Still, even with their brains, they could not compete with tooth and claw.
Enter the six-mile wide asteroid that found the earth 66 million years ago. That asteroid – nudged out of its distant orbit by a chance encounter with another rock or after swinging too close to Jupiter or Saturn – had travelled silently on its way for perhaps a million years to arrive just seconds before the earth moved just beyond it in its own orbit. When it hit, it set the earth on fire and after it had burned away, caused a long dark winter that left most creatures dead and many extinct, including the non-avian dinosaurs. This disaster was, however, good news for the mammals. Perhaps because they were small, lived underground and could eat anything, some survived (along with birds, who are smart flying dinosaurs). Within a million years, the earth had recovered and mammals were the dominant large land animal. Some of those eventually evolved even further in reliance on brains, eventually producing us.
That asteroid wiped the slate clean, resetting the course of animal evolution in favor of the brain and intelligence. There is no reason to assume that an additional 66 million years would have led the dinosaurs towards the Gorn as in 175 million, it had not done so. It’s as if the universe has a bias in favor of intelligence and sent a “do-over” to set things right.