Indeed, sometimes a president for life can proceed to establish a self-proclaimed monarchy, such as Jean-Jacques Dessalines and Henry Christophe in Haiti.
Most were deposed before they died, and others achieved a lifetime presidency by being assassinated while in office.
However, some have managed to rule until their natural deaths, including José Gaspar Rodríguez de Francia of Paraguay, Alexandre Pétion and François Duvalier of Haiti, Rafael Carrera of Guatemala, Josip Broz Tito of Yugoslavia, and Saparmurat Niyazov of Turkmenistan.
Others made unsuccessful attempts to have themselves named president for life, such as Mobutu Sese Seko of Zaire in 1972.
They were never officially granted life terms and, in fact, stood periodically for reelection.