Yes, extinctions can lead to other species having an opening to thrive.
When the dinosaurs left the Earth, mammals had an opportunity to take their place.
Scientists are finding that some evolutions were extremely rapid. I suspect that their model of random mutation is heavily flawed. I also suspect that when God created matter, He included an intelligence of a sort that allows a life form to find a more successful form when the environment changes.
The experiments in California on amino acids on fast collisions proved that complexity can be added by destructive collisions, thus improving the chances of life.
If environment stays relatively constant for eons, as it seemed to do for many periods, then life forms stay relatively constant. When disasters strike, life forms morph toward a more successful form. Those that are not fast enough, go extinct.
Random mutation may have some, little or no part in evolution. The molecular level "desire" to survive is likely the driving force, and life finds a way.