Otoh according to Iain Banks's speculation, space colonisation might be the thing that finally lets humanity toss off the chains of capitalism:

The thought processes of a tribe, a clan, a country or a nation-state are essentially two-dimensional, and the nature of their power depends on the same flatness. Territory is all-important; resources, living-space, lines of communication; all are determined by the nature of the plane (that the plane is in fact a sphere is irrelevant here); that surface, and the fact the species concerned are bound to it during their evolution, determines the mind-set of a ground-living species. The mind-set of an aquatic or avian species is, of course, rather different.

Essentially, the contention is that our currently dominant power systems cannot long survive in space; beyond a certain technological level a degree of anarchy is arguably inevitable and anyway preferable.

To survive in space, ships/habitats must be self-sufficient, or very nearly so; the hold of the state (or the corporation) over them therefore becomes tenuous if the desires of the inhabitants conflict significantly with the requirements of the controlling body. On a planet, enclaves can be surrounded, besieged, attacked; the superior forces of a state or corporation - hereafter referred to as hegemonies - will tend to prevail. In space, a break-away movement will be far more difficult to control, especially if significant parts of it are based on ships or mobile habitats. The hostile nature of the vacuum and the technological complexity of life support mechanisms will make such systems vulnerable to outright attack, but that, of course, would risk the total destruction of the ship/habitat, so denying its future economic contribution to whatever entity was attempting to control it.

Outright destruction of rebellious ships or habitats - pour encouragez les autres - of course remains an option for the controlling power, but all the usual rules of uprising realpolitik still apply, especially that concerning the peculiar dialectic of dissent which - simply stated - dictates that in all but the most dedicatedly repressive hegemonies, if in a sizable population there are one hundred rebels, all of whom are then rounded up and killed, the number of rebels present at the end of the day is not zero, and not even one hundred, but two hundred or three hundred or more; an equation based on human nature which seems often to baffle the military and political mind. Rebellion, then (once space-going and space-living become commonplace), becomes easier than it might be on the surface of a planet.

Even so, this is certainly the most vulnerable point in the time-line of the Culture's existence, the point at which it is easiest to argue for things turning out quite differently, as the extent and sophistication of the hegemony's control mechanisms - and its ability and will to repress - battles against the ingenuity, skill, solidarity and bravery of the rebellious ships and habitats, and indeed the assumption here is that this point has been reached before and the hegemony has won... but it is also assumed that - for the reasons given above - that point is bound to come round again, and while the forces of repression need to win every time, the progressive elements need only triumph once.

Concomitant with this is the argument that the nature of life in space - that vulnerability, as mentioned above - would mean that while ships and habitats might more easily become independent from each other and from their legally progenitative hegemonies, their crew - or inhabitants - would always be aware of their reliance on each other, and on the technology which allowed them to live in space. The theory here is that the property and social relations of long-term space-dwelling (especially over generations) would be of a fundamentally different type compared to the norm on a planet; the mutuality of dependence involved in an environment which is inherently hostile would necessitate an internal social coherence which would contrast with the external casualness typifying the relations between such ships/habitats. Succinctly; socialism within, anarchy without. This broad result is - in the long run - independent of the initial social and economic conditions which give rise to it.