From my experience with people I know and have met in this sphere, it's a combination of people not fully believing in the long term viability of the coins and or the stupid comments of things like "it's only used by criminals blah blah" that makes them not want to stay in it for the long haul. The media hasn't helped in pushing certain negative stories or making it seem like it's this spooky thing the average person should be wary of, as opposed to promoting it as a very viable source of wealth and a way to change the world.