A large part of that income is derived from people visiting her numerous houses rather than interacting with her. There are some exceptionally awesome castles and buildings that should go into National Trust and will still generate wealth for the country. The British monarchy as an institution is greater than the sum of its constituent parts - and one constituent part is the current living royals. I am very interested in the history of royalty and history in general, I do not need a current monarch to spend my money being a monarchy tourist.