Simple theory... If an item is consumable it increases demand, by immediately removing it from circulation once it's used.

SE built a system that would provide the buyer with some benefit via Materia creation vs. NPCing the item for 1gil. As a crafter we ALL deal in consumables now and that can only make it a healthier market for us. This leaves the markets to the crafters so I wont see YOU selling my HQ items for a fraction of their value on the market when you're done with them.

If you don't like the fact that you can't sell the gear I made for you... Make it yourself...