Perhaps the best motivation for going to Mars is political. It is obvious that no single nation currently has either the will or the resources to do it alone, but a consortium of nations and space agencies could achieve it within 20 years.
“America is a place where you can be born into a low-income household but still lift yourself up, and it doesn't matter what color you are.”
“The first point of wisdom is to discern that which is false; the second, to know that which is true.”