What allowed mammals to take over from the reptiles / birds in the first place wasn't some inherent superiority, it was the dying out of all the ginormous hunte

What allowed mammals to take over from the reptiles / birds in the first place wasn't some inherent superiority, it was the dying out of all the ginormous hunter-killers, both animal and plant, that allowed for 'gentler' animals (mammals) and plants (grasses) to emerge. Mammals were there, grasses were there, with all the advantages that their unique physiology gave them. They were just too slow and killable in the dinosaur era to do anything more than just stick to tiny enclaves where the big dinos couldn't get them. After the KT event that killed the dinosaurs, mammals sought to fill the niches left by dinosaurs. They grew big and huge. The few dinos that did survive, sat at the top of the food chain, enormous flightless birds. Sharks took over in the water because all the reptiles that were there were gone. It took mammals 40 million years after the bomb dropped to slowly spread over and gently outcompete the big bads. Collectively. But it couldn't have happened in the first place without Giant Meteor making the choice for us. The Cretaceous was just that gnarly, and it would have only gotten gnarlier. The world found a local maximum, and then that maximum got flattened. The only thing that could have ended it, did.