Did you read the list of extinction-level events in my article? How are you going to "mitigate" gravitational disturbances changing the Earth's orbit? How are you going to mitigate the Earth's axis wobbling, and its magnetic field regularly switching and temporarily most shutting off? Our only hope to prevent large numbers of people dying in all the eventual disasters that will happen is to have off-planet bases of support. Having off-planet infrastructure will also make it far easier to mitigate disasters on Earth like meteorite strikes and Deccan Traps-like eruptions that last for hundreds of thousands of years.