There are constraints written into the fabric of the world which we do not see but are nevertheless there. It’s fun to talk about planetary, stellar, and galactic civilizations as if we will inevitably progress to them; it’s fun. But where’s the evidence of civilizations that came before us? The universe should be lousy with their leavings, the inevitable shitpiles that gargantuan projects always produce. Of course, some say the reason we don’t see any of these things is that we don’t know what to look for. They say it’s like asking a marmot to find a contact address in Outlook; it’s something completely beyond its (and our) ken and ability.
I suspect that the real reason we don’t notice these stellar shitpiles and .pst files is that they aren’t there. I suspect that there are good, unknown reasons that make it virtually impossible for a civilization to spread much beyond where it originated.