Much like UMD, since Blu-Ray was launched as part of a major videogame system launch it outpaced the adoption rate of DVD early on; this (in itself) set unrealistic expectations for how quickly it would be adopted (50% by the end of 2008? yeah right!) and as it begins to struggle and fall below the adoption rate of DVD people will see it as a bad sign for Blu-Ray (which I don't think it is).
In my opinion, Blu-Ray was never destined to become as popular as DVD was because most people will not have hardware which is capable of displaying the improvement over DVD for a couple of years, most users will have difficulty noticing the difference between the video quality of upconverted DVDs, compressed HD video downloads, and Blu-Ray video, and Blu-Ray doesn't offer convenience features which are (seem to be) some of the major reasons why people choose to "upgrade" to a new format.
