Fair point.Not sure that is the case: apparently the Palace of Versailles is one of the most visited tourist attractions in the world, and the single most lucrative tourist site in France.
I'm not bothered about having a monarchy, we're ruled by elected people anyway. I think the Queen does good work representing us around the world, but mostly I'd just like to know if we get value for money, and I think we do, as I'm sure they bring in more revenue than they cost.