Unified Field Theory of Pyramids and the Roman Empire
Can Real Business Cycle theory explain the pyramids?
Well, probably not in the original sense, but try this. Agriculture was the biggest (or one of the biggest) technology shocks in human history. The result was an immense concentration of work and leisure. Now most labor could be concentrated in a few months, and subsistence on the proceeds was possible for the rest of the year.
Because food had to be stored, this produced a social instability. Capital and food storage capability became concentrated in a few hands. The result: a few rich and starving masses. The starving masses, left to their own devices, would need to become bandits and pillagers, which turns out to be bad for almost everyone.
Solution: put the masses to work. Pyramids and other building projects have been popular for much of human history. War is another favorite. The Roman empire was won by farmers fighting in the off season. The Aztecs and other meso-Americans pursued both strategies.
A plausible argument could be made that the creation of the European empires was a similar response to technological unemployment.
It should not escape our notice that we seem to have entered another period when technology is displacing a large number of workers.