“The path to the deserts of the moon and mars leads through the deserts of earth.”
I have no problem with that argument.
I only suggest that invention and practicality do not always go hand in hand, and the water idea, to meet the economic burdens related to necessity, will see much more practical adoption of that technology in “off world” situations than on earth.
There are over 40 minerals and metals in seawater. If those could be extracted profitably—then that technology can be transferred to the moon and mars and refined to take into account different elements dissolved into moon and mars water.