Echoing a few who already spoke about it but the fact the "rarity" was solely based on its scarcity, which was compounded when they stopped making the cards, and allowed outside forces (scalpers, others) to dictate its value rather than a static price or achievement based gives a lot of rational for the classic TBC premium items or Bananas from the newer donations.
If these items had been oriented around something in game, an achievement, I would definitely be up there defending the exclusivity of the items. The defense of a temporarily available product through a system intentionally created for you to -potentially- spend an absurd amount of money isn't going to get a lot of traction from most folk.