He has not sold it for a LONG time (week 4). There are a lot of players that did not start day 1 nor have enough strange coins by week 4 (aka me). That is why some don't have it, yet. I have 800 hour or so and have never had it drop even thought I GRIND. It was the last exotic (Non Bounty) I needed. So grinding does not guarantee the drop. So its nice to have the option of Xur after I grinded my SCs. I had 81 of them before this week. :)