Couple of days before it got mentioned in the latest Bombcast, I checked out Curiosity after not having it started for weeks. Maybe it's just me, but I feel like this "game" has burned out fast and is now struggling to keep any momentum in terms of active users constantly digging at the cube. I remember during the first days they mentioned, that because of the high amount of new players 4 layers were chipped away in 24 hours. Looking at the stats now, it seems like the ratio is somewhat close to that (if not less) again, although the cube is actually smaller.
My point is: I cannot imagine this thing beeing finished in even two years. I just don't think that enough people will keep on chipping constantly.