For the colony to be truly self-sustaining it would have to replicate the entire industrial supply chain for its technological and material needs. Without it, t

For the colony to be truly self-sustaining it would have to replicate the entire industrial supply chain for its technological and material needs. Without it, the colony and its infrastructure would slowly crumble apart. In such a situation, we could always go back to basic agriculture and hunter-gatherer lifestyles on Earth. Most humans would perish, but the species would survive. That option does not exist on Mars before self-sustaining terraforming. Putting boots on Mars doesn't help solving the above problem. As TA explains, the first humans would be mostly busy surviving and would be dependent on permanent resupply from Earth. It's a pure prestige project. The effort would be better spent on engineering a streamlined and automated version of our technological base that can be deployed with minimal effort and supervision to set up a colony or a mining base. Once we have achieved that, we are on the way to become a post-scarcity civilization and can easily push much farther than Mars.