No matter how spiffy your new hardware or software is, something spiffier is will be released soon. The computer market evolves faster than any market before even dreamed of. If you wait for the next generation to come out, the one after that will be announced. This is related to Fact Two above. Devices and programs drop in price when newer ones are released.
Prices also drop from competition among similar products and as manufacturing techniques improve.
At first they were only available for publishing software in bulk and cost thousands and thousands of dollars. Well, maybe not. But I wouldn't be surprised to find that writable CD drives soon become standard on new systems and thus be included in the system's price. The other common pattern is for the price to remain steady but the capacity of the device to improve drastically. This is what has happened with hard drives.