As I said I am not a fan or a salesman for Inkjetmall (Cone))
Jon Cone sells high quality expensive inks to a discriminating group of photographers. All of these photographers / printers have to use refillable carts. Most will probably purchase these carts from him. It would not serve his business model well to sell anything but an absolutely top of the line cart. They would not tolerate an inferior product. As far as I can see most of the other suppliers are in this to sell only the carts and have little motivation to demand anything but the lowest volume price.
Kelly