I think that the question is how monarchy is defined. If the US would declare G.W. Bush King George the Great, and change nothing else, would the US be a monarchy now, and if so would that somehow magically chance the social environment? I doubt it [:)]
My understandding is, though i have not read intensely Hoppes ideas on that, but concluding from his overall point of view I think I understand, he refers to the feudal monarchical system, where the king was only a sovereign over his own estates in terms of property and had some extra rights (by contract) to call the barons and dukes in for war (only for a specific period of time a year). Other forms of government, even if the head would be called a king, Hoppe would not mix mith monarchy but would call it by the proper name like despotism, oligrchic etc. Yet, again this is just an educadet(more or less) guess.
The fact that the catholic church had such a huge influence in the power struggle is primarily based on the double allegiance of the peoples to King and church. Yet, the church was an international body, i.e. the catholic church was equally present in france, italy, in western europe for short. So the people in each of these countries where first of all christians, not italian, french etc. Even more a thing like france or italy didn’t even exist. People lieved in areas that where ruled by a knight, a duke or a baron, not by a national government. They had a double allegiance. One to their sovereign (the knight, baron or duke) one to the church, which had a universal sovereignity in issues of faith (which was much more important than today) and had a lot of folks (priests, monks, bishops) spread out all over the baronies and kingdoms in western europe. Means they where pretty present in everydays life of the people, much more than the secular sovereign was. If some prince or knight wanted to raise taxes, which they always wanted, one could just leave the realm of that prince and go somewhere else, as there where all christians and there was the same church, with the same priests, monks and ritual. In short, people where relativly free to search a better place, very different from what was the fact in despotic countries, where the peoples where enslaved as bond slaves like in russia.
So the relativ freedom in europe during the feudal era was higher than anywhere else in the world we know about, and for sure higher than in the following centuries when absolutism centralized all power and souvereignity into the hand of the absolute monarch and his bureaucrats.
An interesting side note here is, that the rise of absolutism goes along with the rise of the court. Kings wanted to have their aristocracy close to them rather than sitting in their baronies and challenge the kings rule. So the court system emerged, and, because the now useless barons and dukes needed something in exchange for feudal skirmishes and occasional wars, the whole system of good manners and courteous behavior (and the intrigues at the court as well) arose.