Monarchies didn’t just collapse. They were deliberately dismantle to make way for systems that excel at short-term power grabs but fail miserably at long-term stability, tradition, and protecting our property rights. Funny how that worked out, isn’t it?
Monarchy's legit because the monarch has been chosen by God. In a godless society this means they have no good reason to rule. So good luck with restoring monarchy. It's a decoration in the West at best. At worst it's an unnecessary expense I agree that what we have is not perfect and perhaps not even good but this doesn't make an easy case for the system you're advocating for Which is a shame because if the king is good then country does well
God actually advocated for and originally established a Theocracy. I think going through all phases and systems is part of humanity being reconciled to him as beings who understand the nature of good and evil. We are becoming more like him. Ironic that the snake in the garden was actually speaking the truth. Because through the sacrifice of Christ on the tree we shall surely not die, and we shall our knowledge of evil but choosing good.