>Civilizations would have to plan ahead and estimate the supply and demand many years, centuries or millenia into the future.
With even informational signals taking years to decades to centuries each to reach their destinations, our current knowledge of physics implies that a civilization basically needs to achieve indefinite cultural lifespan before they can do anything interstellar whatsoever.
So once you've got people who can maintain records and culture over centuries on detailed matters (or who just plain live that long), it's really not that much of an obstacle. But it's a nastily high mountain to climb in terms of bootstrapping your interstellar empire.
With even informational signals taking years to decades to centuries each to reach their destinations, our current knowledge of physics implies that a civilization basically needs to achieve indefinite cultural lifespan before they can do anything interstellar whatsoever.
So once you've got people who can maintain records and culture over centuries on detailed matters (or who just plain live that long), it's really not that much of an obstacle. But it's a nastily high mountain to climb in terms of bootstrapping your interstellar empire.