Thanasis
An item's sale price often reflects the costs and effort that went into creating it. Plus, retail prices will be higher than the actual production cost. Otherwise, no one would make any money.
Plants, especially slow-growing, temperate climate perennials, are no different. In addition, orchid seed germination is no simple task (for the average hobbiest anyway). A mature cypripedium plant easily has 4-5 years worth of time put into it, not to mention the cost of the products used to aid germination, potting material, greenhouse space, etc. What's a grower's time worth? It's hard to say. I know I wouldn't let a plant go for a bargain price if I had put years into it.
I feel the prices most cyp growers offer are quite reasonable, given the nature, and popularity of the plant.