The basic principle of every game: People buy it. Of the people who bought it probably 75% will stop playing within a month. Out of that 25% left about 50 % leaves after 3 months or so. The rest will be the core players and the will stick to the end. The game wont die. Eventually we need to trust bungie. If after 6 to 9 months things didn't change... Then we have a good reason to demand more. That's my opinion.