True. Saving earth would be much easier in almost every way imaginable (economic, logistic, structure) than trying to establish a new earth in space. Not saying we should not explore possibilities, but human sense and desire for exploration was always driven by the search for places that are good for humans to live in or provide value to our direct needs, while space is so hostile to our race that the efforts would be enormous and the benefits little. We have been to the moon, but found nothing too valuable and efforts have largely scaled down since then. We humans are bound to earth by our very own evolution, finely tuned for this environment. We are children of the earth and children we will remain.