My guess would be it will continue to increase in price, but not by huge amounts; just incrementally each year. Synthetic Ivory has gotten so good that I for one will never buy elephant ivory again. It doesn't look any better, the feel is the same, and the synthetics are WAY tougher than Ivory.
Personally, I'd like to see the ivory trade put to rest. Sure there is legit ivory out there, but there is SO MUCH that isn't. For presentation grips, I like Walrus and Mammoth better. For a combination carry/presentation, the best of the synthetic ivory is the way to go.