It could be a huge variety of things. Maybe one company they all used went under. Maybe there was a bust. Maybe there was a global event (fire, flood, war) that has messed with the connection to an essential part of the system.

Whatever it is, it isn’t a good idea to make it public unless it really is the absolute end. Doing so only reveals how the system works, which makes it weaker. All anyone can and should do is simply wait and keep seeding.