>>715098985
If you don't choose Mr. House humanity will never leave Earth. The war stripped the Earth of it's major resources and surface minerals and good luck reviving international trade between nations that nuked each other.
Caeser wants to set a foundation for future civilizations, but that's pointless because those future civilizations won't have access to the high tech like House does (the Legion's tech hatred will ensure this).

The only way for Earth to be saved is to collect resources off world. The Earth's resources are too used up for future civilization's to figure out how to leave Earth.