Harry and Meghan's wedding cost £30 million. The amount of money we spend maintaining the lavish lifestyles of the Royals has far better uses. Given limited government funds, we should not be spending taxpayer money on an elite group of individuals who contribute very little to the country  . The Royal family are a net drain on public finances that is taking money away from more important causes. The money spent flying the Queen around the world can provide free school meals or repave country roads. The money spent on the extended royal family, their travel, premises, security etc far outweighs any income they generate. While the Family does bring in money by attracting tourists, the historic locations will continue bringing in visitors regardless of who lives there. Buckingham Palace and Windsor Castle will continue to be important landmarks that people will want to see, much like Versailles continues to be receive thousands of visitors despite no royalty living there for generations.
The Royal family brings in more money than it spends through tourism. Its existence sells merchandise, creates an invaluable marketing tool and creates a buzz around the nation in general. The Royal Finances are transparent and accountable. This means that excess spending will likely be caught and prevented. If the Monarchy isn't actually a substantial drain on public finances, and brings in other substantial diplomatic, PR and soft-power benefits, we have no reason to abolish it.
[P1] Spending large amounts of limited public funds should be justified by a large amount of benefit for the British public. [P2] The Royal family is a net drain on public funds. [P3] The Royal family does not create a proportionate benefit for the British public. [P4] Therefore, we shouldn't spend money on the Monarchy and it should be abolished.
Rejecting the premises
[Rejecting P2] This is untrue. Most sources show that the Royal Family is self-sustaining and actually benefits the British economy.