Don't get me wrong, if he was selling I'd be buying. But that would make it way too easy for everyone to hit the cap. You're not supposed to have every single piece of armor leveled up as high as it can possibly go. Thats just not supposed to happen. Maybe if he had a cap on the amount he sold, like 1 per week, that would be ok. But if he sells it like exotic shards, i.e. all you can eat, then that would suck in the long run