Oh, a benevolent monarchy (or a benevolent dictatorship of any sort) actually has the potential to work pretty well. The problem is, there's no way to assure that the monarch will always be benevolent. Not to mention competent to do the job.
Which is why, after experiencing one, the population tends to develop a strong preference for some other form of government. Assuming they have heard of one, and can imagine living under it. Sometimes they deal with that by emigrating to somewhere that provides that alternative. Other times, they rise up, eliminate the monarch (and his supporting cast), and try to set up something better. It can take a few iterations to get the necessary, but not always obvious, checks and balances in place.
Oh, a benevolent monarchy (or a benevolent dictatorship of any sort) actually has the potential to work pretty well. The problem is, there's no way to assure that the monarch will always be benevolent. Not to mention competent to do the job.
Which is why, after experiencing one, the population tends to develop a strong preference for some other form of government. Assuming they have heard of one, and can imagine living under it. Sometimes they deal with that by emigrating to somewhere that provides that alternative. Other times, they rise up, eliminate the monarch (and his supporting cast), and try to set up something better. It can take a few iterations to get the necessary, but not always obvious, checks and balances in place.