There are other counterexamples to the theory that free societies are likely to found among islands, swamps, and mountains. For example, Polynesia was noted for islands being governed by absolute monarchs.
In Western Civilization, it was hard to establish a tyranny over an island because people could move to a neighboring island but it wasn't that easy for the king to conquer the neighboring island. <wild-guess>I suspect that in Polynesia the islands were too far apart for private citizens to escape.</wild-guess> Do I have any readers who might know something about Polynesian history?
If the above scenario is true (Polynesian islands were close enough for a government that could draw on the entire resources of an island to organize sea travel but it was beyond private means), that has implications for the future of freedom. In other words, we had better find cheaper ways to get off the planet.
On the other hand, if space travel is too easy, that might lead to scenario resembling Japan, in which the islands were close enough for a government to conquer the whole archipelago.