Maintaining an adequate technological basis for continued survival on Mars requires, simply, many, many times more people than Mars could support. So, all the m

Maintaining an adequate technological basis for continued survival on Mars requires, simply, many, many times more people than Mars could support. So, all the more tricky components and chemicals have to come from Earth. When those stop, the technological basis soon declines below the level that can support the population living there. All the choices after that become very unpleasant, of questions about who gets to continue living. The supportable number declines inexorably to zero.