double blind plausibility check

How likely would it have been for Rome and Carthage to end up as mortal enemies, rather than firm allies?

How likely would you say it is for Samaritanism to end up as one of the least common religions in the world?

How likely would it be for at least a simple majority of the world's population to follow one Abrahamic faith or another?

One thing I find very interesting is the fact that the predominance of monarchism has lasted so long. Granted, monarchs generally don't enjoy the kind of power they had in past centuries, but the monarchy remains the most common type of government by far. How plausible is it for most countries...