If we assume that the position and powers of the Princeps rose and developed subsequent to the Republican Civil Wars ending, following Octavian's return from Egypt (after he had defeated Antony and Cleopatra at the Battle of Actium in 27 BC), we can see that such wars had created a situation in which a system of rule under the 'Princeps' or ('first among equals') might take root and flourish.
The traditional source of political power in Rome, the Senate and it's Magistrates had been reduced to a nearly powerless shadow by casualties of war, proscriptions, the economic impoverishment of many members and the corrupt behavior of others. For decades, real power had been in the hands of generals who had been dictators in fact, if not in name. Marius, Sulla, Caesar and the triumvirs had all used the Senate as an instrument of their will and as a rubber stamp for their own political decisions, whilst holding onto real power in the form of their armies.
Rome and Italy had been reduced by the economic chaos of the war and the exactions and confiscations needed to support the armies.
The Empire itself, whilst it had grown was only weakly held in many areas. Gauls in North Italy were trying to break free of Rome, parts of Spain were virtually unconquered and Parthia threatened in the East. Rome held an Empire in name, but could derive little benefit from it, economically or otherwise.
As a people, the Romans would have been war-weary, national self-confidence would be at a low ebb and faith in religious certainties lost. (Evident in the people turning to foreign Gods such as Isis).
Whilst a triumvir, Octavian had annihilated the staunchest Republicans and came back to Rome as a man, wise enough to avoid the...