[theonemind]

France abolished their monarchy. I think the other monarchies took note of this and decided to simply live a life of power, prestige, and influence and not get their heads on a pike by ruling like tyrants.

I think if they tried to exercise major operational control in government, it would trigger revolutions, formal republics, etc.

Reality is usually a bit more nuanced than the formal rules on paper. We have all kinds of laws on the books that don't really apply. Likewise with many of the supposed powers of these monarchies. Without exercise, exercising them makes them legal in the same way killing a home intruder is legal. Legality doesn't mean exercising it won't be bloody, won't have cost, won't have risk, etc...legality one way or another doesn't matter that much.