[dogma1138]

Markets can very well fuel demand, new products, advertisement and artificial scarcity can fuel demand rather well. Much of modern economics revolves around not only fulfilling demand but also creating it.

If there was no way to acquire legal Ivory and all forms of Ivory would be illegal and culturally unacceptable people would want it less, if it will be viewed as morally abhorrent to have an Ivory statue as a center piece in your living room less people will want it.

If artists could not get their hands on Ivory they will result in using alternative materials, most people don't want a block of Ivory they want a masterfully crafted art piece again driving the overall demand for Ivory down.