While it may be true that history is an unreliable predictor of future events, we should not forget that it was only about 50 or so years from the the assassinations of the Gracchi Brothers to the end of the Roman Republic and about the same length of time from the death of Pericles and the destruction of Athenian democracy by the treason of Alcibiades. It has also been about 50 years from the assassinations of the Kennedys and the rise of Trump.
Athenian democracy lasted a scant 100 years and the Roman Republic a little more that 300 years from the sack of Rome by the Celts under Brennus. The United Sates can be viewed as having existed for 245 years from the Declaration of Independence until now.
It each case the Republic or Democracy rose through the defeat of the interests of the inherited wealthy classes of their time and in turn destroyed by a member of the same wealthy class claiming to be a friend of the people.