They did pay more. Sony took the money they got from their customers and used it to sign exclusivity deals with developers. Microsoft used their money to build a stupid little camera and add voice functionality that no one wanted. Its basically a subsidy paid by Sony to drive up their console sales. All companies ultimately derive their income from their customers, Sony invested some of that income into Destiny. They effectively paid for the development of exclusive content using their customers money, so as far as Xbox is concerned if and when they get those exclusives its basically just a handout.