People don't understand what happens in things like this. Destiny starts off slow selling little things that help players get things a little easier. Slowly they will start adding more and more for an increased amount of silver. They are gonna test what they can get away with and then push it a little farther taking advantage of the money people are willing to spend. Next thing you know strange coins are being sold and Destiny secretly decreased the amount of strange coins being dropped in game. Xur comes strange coins are scarce and xur has something the person really wants