They're pricey because they were bred down from 3 red showing individuals found in a batch of about 3,000 pale blue shrimp by a guy in japan. These were then bred for individuals showing the most red and white for several generations until they got what we call crystal red shrimp. There are even grades within this that differ with how much white they show. Having all been bred from the orignal 3 shrimp, they don't have much genetic differentiation and don't adapt well to less than ideal conditions.
Shipping them to america is pricey and there's huge losses when they do this. These aren't very hardy shrimp and it's not worth the risk for most LFS. Once things really get going in america the prices will drop. For now there's pretty high demand for them, and not much supply.