I don't think that's accurate. My 2007 hatchling pastels were worth $225, and are currently worth about $400--next year, I expect they will be breeding-sized, and worth about $700. The year after that, I expect they will have dropped to only about $600, and that's 3 years later. But the price may not drop as quickly as that--breeder-sized morph females are always in high demand, which keeps the prices high. Don't underestimate how well ball morphs hold their value even in THIS economy. This year's price drops are not indicative of the norm, and they apply primarily to hatchlings--prices on adults haven't dropped quite as severely.
In general, adult female normal prices seem to be about $100 per $1000 grams--with some leeway for deals. That's been the case for years, and I expect it to continue to hold steady.