So your suggestion would be . . .?
But the outright winner in stability, longevity, and relatively minor corruption, is a Monarchy.
The trouble is; change is slow, and young fire eaters need turmoil to create openings for personal advancement. A clever King finds outlets to burn off that excess energy. A lazy or vain one lets the generals create an empire.
It takes a lifetime of training to be a Monarch.
In America, we let failed lawyers, ruined businessmen, and professional bureaucrats run the country. We can do better.