I think that there will always be a demand for the more unusual high end morphs..the simple single gene animals are being produced more. therefor not difficult to source, as a result the prices are dropping.
It is only reasonable to expect the cost of your morph to drop..if you are buying the animal solely as an investment, you will still recover your initial outlay as you will breed the animal for many years returning on your initial investment..if you can not accept the decrease in value..do not buy