They don't mean "in trouble" as going to fail. They just mean "in trouble" as adoption is fairly slow, well behind DVD adoption and the twin spectres of VOD and Digital Distribution hang over everyones heads.
Very true it is slower, but also keep in mind that DVDs didn't require a new TV to get the full benefit of the format, where Blu Ray's advantages hinge on HDTVs. I am curious how digital distribution is going to turn out, but that will depend heavily on bandwidth and overall availability.
The main problem with Blu Ray is that it is moving parts. Seems like an odd complaint but when you take into account how eagerly they're working on solid state drives and things that are more energy effecient and less likely to break I get the feeling that it'll live side by side with DVDs and disc media in general is going to disappear. Flash drives, SD cards are getting bigger and bigger, and they're working hard and harder on making it all cheaper.
Nintendo will return to the glory that is cartridges which NEVER DIE NO MATTER WHAT.
In other words, I think there will be some kind of physical media out there because physical media is security. It's not going to disappear into cyberspace or get hacked and peeked at. It's right there on the shelf if your computer shits the bed. I just really don't see discs suriving and sooner than later Blu Ray go the way of its 5.25, 3.5, and record spinning buddies to the land of spinning, loud, unreliable, power sucking relics.
3rd Party Wall of Shame