another interesting academic question... PTS is different than any other altcoin. If every miner in the world suddenly stops mining PTS, it still has value. PTS, at that point, has become just like AGS. An untradeable asset that represents a share in future I3 DACs.
If every miner in the world stops mining litecoin, it becomes worthless. PTS is different.
EDIT: of course, it is more valuable if it is tradeable. But it is not valueless.