When and where?

>But the older I get, the more skeptical I am that the social class just below the monarch would blindly subject themselves to the monarch's authority for the sake of upholding tradition.

They never did. The nobility had no problem revolting or disobeying in states that were often sorely lacking in centralisation; Magna Carta was practically signed at swordpoint for instance, by King John, who was compelled to do so by a bunch of rebellious nobility.

You are not talking about a modern state where we all reluctantly agree to elect a leader, and that leader wields vast power we have no access to. You're talking about a tiny minority who already has an enormous amount of power (physical, financial, political, social, etc) being kept somewhat in line by constant application of power-sharing agreements and marriages, competition, open violence and threats, gifts of land, money, and so on.