My partner and I were discussing the reasoning behind the high cost of the hotel transfers at the Waldorf Astoria Maldives. Our theory is that the Waldorf Astoria Maldives is setting the price of the transfers based on the idea of the transfer "business" as a separate entity from the hotel. In order for the "business" to be profitable, the price of the transfer must account for the cost to purchase and maintain the yachts used in the transfer separately from the hotel.
They probably got this idea from the Conrad Maldives where the transfer "business" is profitable and probably treated as a separate entity. In that case it should be treated separately as the hotel doesn't own the seaplanes.