It is fallacious to argue that because the Russians or Chinese are (allegedly) able to decrypt the Snowden files, there is no need for Western intelligence agencies to worry about the prevalence of encryption. Assuming that the Russians or Chinese have obtained copies of the files (and they surely have), they would know that they are hugely valuable, and would be willing to put a correspondingly huge effort (human and machine) into decrypting them. This effort might include traditional methods such as blackmail, burglary, and honeytrapping to get information about passwords, etc. How many journalists and others have that information? How many of them are deeply hostile to the West? (Most of the staff of the Guardian for a start!)
The problem of mass encryption is entirely different. The intelligence agencies might have hundreds of potential suspects. It would be quite impractical to put as much effort into all of these as the Russians and Chinese would be able to put into Snowden. Quite apart from the fact that the Russians effectively have Snowden in custody already.