The argument I'm making is that self sufficient colonies are so far away that building non-self sufficient colonies isn't on the critical path. The basic probl

The argument I'm making is that self sufficient colonies are so far away that building non-self sufficient colonies isn't on the critical path. The basic problem is the productivity needed is enormously higher than what we have now. Today, a large number of people can support a small number of people in space -- and that's with the high productivity we have with industry optimized for Earth (where, for example, repairing things and dissipating heat are much easier.) To make a colony self-sufficient, industry has to be so productive that supporting one person in space takes the work of fewer than one person. And, that productivity has to be in space. Not just building spacecraft and stations, but all the necessary materials and interlocking webs of devices and services that an industrial economy uses.