The value of materials on Mars will need to take into account the incredible expense of moving the material off planet. It's unlikely that will ever be cheaper

The value of materials on Mars will need to take into account the incredible expense of moving the material off planet. It's unlikely that will ever be cheaper than recycling the materials we have here on Earth. This is especially true if Planetary Resources succeeds in mining asteroids. If we can get cheap resources from our asteroids, getting them from Mars will be out of the question. Orbital mining and habitat construction is roughly similar level of difficulty and much more economically viable. If we go to Mars (and we should), it won't be for pure economic reasons.