Unfortunately (even ignoring chemistry/matsci), one of the answers to that is simply "natural ivory is becoming a scarce resource". When something is scarce, i

Unfortunately (even ignoring chemistry/matsci), one of the answers to that is simply "natural ivory is becoming a scarce resource". When something is scarce, it becomes sought after, which can result in it even becoming a Veblen Good[1] over time. [1] https://www.investopedia.com/terms/v/veblen-good.asp https://www.investopedia.com/terms/v/veblen-good.asp