First thing : let's evacuate right now that old song and that UK article " Yes but the Crown brings more money than it takes ".
I know there're still many kingdoms in Europe, and in other continents. Generally, the " nobles " are very, VERY rich. Europe is having hard times, but some countries still " pay " their nobles. Not that they deserve it, they're just well born at the right place, from the right noble uterus. How can it be that some countries ask efforts to their people, have cuts in public and social services, but still allow their nobles to " hold their rank " ? UK is the only monarchy we really hear about (Oh, a fantastic well born new baby ! How're they going to call her/him ? An old first name for sure. It's fantastic, I don't know why, but it is, and it will make my life better !), the spanish one, or the swedish one sometimes. I don't get how you can mix a very liberal economic way of thinking and keep monarchy side by side ?