For that matter, most of the entire world civilazation had monarchies of one sort or another. There is no goundswell of popular opinion anywhere to restore such a political system. The example of Malaysia is a poor one. That was the result of a compromise of post-colonial power-brokers. And, not all agreed to be part of it. Brunei & Singapore opted out and not all of Malaysia is monarchy in form. I m a big fan of the EU concept. And I can see, perhaps, in the future, Head of the European Union, but not in any way dynastic. The cultural diversity involved just would not support such a creation. Remember such a project has been tried before, on a much smaller scale than what is now involved, and that did not work- on the principal of monarchy. I think that only in established long-history monarchies, where the sovereign is pretty much universally admired and respected by the citizens will the institution survive.
As for the former monarchies [and not a few current ones]- not a chance.