I've opined in another thread that the video industry seems to repeating the mistakes of the audio industry. This is the battle royale between SACD and DVD-A that somehow never made a dent on the CD's position as the dominant audio format. Audioholics seems to get it right - a format war, very few titles, and the absence of any timebound gameplan from recording studios to phase out the old format ensured both DVD-A and SACD can only muster a small niche market. In fact, in the age of internet downloadable audio streams, the emergence of MP3 over the last few years seems to indicate it is now head to head with CD as the dominant audio format and could be the one to overtake CD.
The same could happen to HD-DVD and Blu-Ray. With such underwhelming debuts from either camps, it will be a long steep climb for either to phase-out the very popular DVD format. The only way to phase out DVD is for the studios to declare no more new titles in DVD format - something I doubt they will do.