How do we bootstrap to the point where we eventually have factories in space? If it were up to me, I would be researching and optimizing non-chemical propulsio

How do we bootstrap to the point where we eventually have factories in space? If it were up to me, I would be researching and optimizing non-chemical propulsion, also green synthetic fuels for launches. Unfortunately, we will have to leave that for some firm other than SpaceX to develop.