Simple answer as to who is mainly at fault for high DDR prices: Intel. Why? For the first few months of the Pentium 4's life, the only option was RDRAM. Then Intel allowed for SDR SDRAM to work with the P4 via their i845 chipset. P4 sales rose b/c people were kept away due to high RDRAM prices. Now the P4 has three chipsets that allow it to opperate with DDR SDRAM. Intel has dominated the market for quite some time, so now that it's flagship CPUs, the P4s, can work with DDR SDRAM, prices for P4 systems fell because DDR was cheap and very abundant at the time (DDR was also a much faster solution than SDR). RDRAM had never really caught on even though it still does offer superior performance for the P4. So DDR is now all the rage and P4 systems are engulfing the supply of DDR. Low supply + high demand = high prices, all primarily because Intel allowed the P4 to stray from RDRAM. Good thing for Intel customers, bad for those who go AMD.
It'll be some time before the market has some time to recover and meet the demand of DDR. Prices should begin to fall, but maybe not. DDR333, 400, and 533 are supposedly on the way, which doesn't encourage the production of DDR266. Who knows, prices for DDR may not see a significant drop for quite some time. It wasn't too long ago that one was able to snatch up a lot DDR ram when it was about $36 per stick of 256MB (even for Crucial).