It seems to me that the open society is in a perpetual state of trying to outrun an endless sequence of problems: would-be invaders from closed societies, internal activists who would rather close down the society in the name of stability, exhaustion of resources on the planet, solar system, and so on, the inevitable asteroid impact or supernova, etc.

And the idea is that this endless sequence of problems exists regardless of how open your society is. So even if you were able to implement a perfect set of authoritarian rules to establish a stable closed society with the technology to capture all the resources from the solar system and redirect all dangerous asteroids, well crap, you still weren't innovative enough to stop the supernova from killing everyone 200 million years later.

Seems right to me