Those major extinction events were probably because of a giant field of giant space rocks. The Earth is moving along with the Milky Way Galaxy in a circular pattern. Part of that pattern involves traveling through an ORT Cloud. The ORT Cloud is the giant field of giant boulders. A space rock say 5 miles wide smashes into the Earth and there could be lots of damage. Maybe next time there will be rockets to blast the space rocks into dust so the Earth will be saved.
The meteor that hit the earth at what is now the Yucatan Peninswas and wiped out the dinosaurs 65 million years ago was six miles wide.
Pain killer meds, anesthesia for surgery, vaccines, prescription meds etc are less than 200 years old in earth’s age of 5,000,000,000 years.
Humans will become extinct in less than a 500,000 years based on how popular cocaine, heroin, booze, ganja etc is now. We are living in the golden age of human civilization. Enjoy it!