Maybe some evolutionary steps prevent them from happening again in other branches, because they take over the world so quickly? For example human intelligence

Maybe some evolutionary steps prevent them from happening again in other branches, because they take over the world so quickly? For example human intelligence might have quickly wiped out or constrained to small populations all other mammals on the path to the same level of intelligence? Early forms of life may also have multiplied so fast that all chemical resources useful for it became involved in the "lifecycle" of life and hence were not available for other types of life to evolve.