While it currently looks like the human population will plateau, there is no guarantee of this; if it returns to exponential growth, and if we are limited to the speed of light, then we get exponential demand increasing with polynomial supply.
How much this matters to you depends on if you prefer Total
Human Product or Product Per Capita.
But if you care about GDP (i.e. of a nation not of humanity as a whole or average per person), the maximum size of any plausible zone of control for any government is likely to be in the order of a solar system or less, based on the historical precedents of communication lag between empire capitals and outer colonies — exponential growth makes this happen faster than you might otherwise expect.
While it currently looks like the human population will plateau, there is no guarantee of this; if it returns to exponential growth, and if we are limited to the speed of light, then we get exponential demand increasing with polynomial supply.
How much this matters to you depends on if you prefer Total Human Product or Product Per Capita.
But if you care about GDP (i.e. of a nation not of humanity as a whole or average per person), the maximum size of any plausible zone of control for any government is likely to be in the order of a solar system or less, based on the historical precedents of communication lag between empire capitals and outer colonies — exponential growth makes this happen faster than you might otherwise expect.