The Space Review: The other side of the Fermi paradox

The Space Review: The other side of the Fermi paradox: "If extraterrestrial civilizations do not exist, it is even more important for humans to survive and colonize space. If we do not do it, then no one else will. If extraterrestrial civilizations exist, the task will be shared. In any case, the ultimate goal for all civilizations is to spread life throughout the galaxy, to transform a largely dead galaxy into a living one."

No that is one heck os a "Manifest Destiny". Are we up to it? Is perhaps the % of livable planets much lower than we have reasoned?