It is interesting that the Eastern Roman ('Byzantine') Empire, which lasted for 1000 years in Constaninople - much longer than any other polity since Christ - managed to get the benefits of bureaucratic organisation but without suffering its tendency to unchecked metastatic growth; by the simple means of restricting membership to eunuchs.
Life as a eunuch bureaucrat was pretty good - and although you were not allowed to be Emperor, you could rise to being Patriarch of the church (e.g St Ignatios) or chief general of the Imperial army (Narses); and (on average) you would live longer (and healthier) than an uncastrated man.
On the other hand...
Note: A further important factor in its longevity was the highly religious devoutness of Byzantine life, which seems to have continued pretty-much unabated throughout the 1000 years. This motivated people; and to a significant unified and directed this motivation outside the individual mortal life and indeed the world itself; which maintained cohesion and kept a check on wholly-selfish short-termism.
