Maybe downloadable content will be the winner much further down the track, but for the moment I think the problem is that Blu-ray hasn't done enough to dethrone DVDs as the standard format.
Think about what DVDs had to offer over VHS - much smaller form factor (you can get about three TV seasons worth of content in a case the size of a VHS tape), significantly increased quality (both picture and sound), the ability to choose subtitles in dozens of languages with a click of a button, no rewinding, multiple soundtracks on the one disc, selectable camera angles, chapter selection, usable menus, special features, audio commentaries, no degradation of the signal from repeated use, etc...
Blu-ray offers... a slightly better picture. If you fork out ridiculous amounts of cash for the new discs, players and a HD Television to go with it.
Sure, I can tell the difference, and so can most people, but DVDs are actually reasonably good quality to begin with, and good enough for most people out there, myself included.
Clearly you have not heard of BD-Live?!
And yes, she is an actual registered participant who qualified by finishing among the top 100 women in the Houston Marathon in 2006. NASA's press release touts this as yet another space first:She says she is doing it to motivate children to be fit. "I encourage kids to start making physical fitness part of their daily lives," Williams said. "I think a big goal like a marathon will help get this message out there."
"She will run the famed race in April as an official entrant from 210 miles above Earth aboard the International Space Station. This will be the first time an astronaut in space will be an official participant in a marathon.
If the human brain were so simple that we could understand it, we would be so simple we couldn't.