That's exactly the point. If the demand for Mojaves, or any morph for that matter, exceeds the supply then the price will remain higher. Until it reaches the point when supply is equal to demand or when supply exceeds demand the price will not drop sharply. Another point to consider is that, as prices in general drop every year, more people can afford to buy combos such as Bumblebees and Pastaves and bypass the base morphs such as Pastel and Mojave.