Because, according to yesterday’s Guardian, his income – including funding from the taxpayer for his official duties – rose by nearly £1m last year, according to figures published in the annual review of his activities.
As in previous years, the review stressed the prince’s charitable works, claiming that he had helped to raise £123m directly or indirectly for his 20 core charities, and also the household’s continuing commitment to the use of environmentally friendly energy sources. It claims that total carbon emissions fell by 22% and that nearly a third of the energy used comes from renewable sources. Solar photovoltaic panels have been installed on the roof of Clarence House in London and on barn roofs around the farms on the prince’s Gloucestershire estate at Highgrove.
One item of conspicuous expenditure not listed in this year’s review is the cost to the family of the royal wedding at the end of April and is unlikely to be detailed next year either. The aide said: “What really counted was the happiness of the occasion. I am not going to say how much money was spent. Obviously, the Prince of Wales spent the majority of the costs but I don’t think generally people say how much weddings cost do they?”
Eric Koch’s book, The Weimar Triangle, is available at Indigo-Chapters and in your local bookstore. 
The Guardian is an anti-monarchist paper with a left wing agenda that would make the Toronto Star blush. That said, Prince Charles and his horsey wife are most un-attractive.