To get a good perspective on why there is no need for an organzation to act as a keeper of the truth I recommend the following book:
The Catholic Church - A Short History....By Hans Kung
Hans Kung is basically a catholic Ray Franz (He is even mentioned in COC towards the beginning). He held a high position in the church and had his own crisis of conscience which led to the writing of this book.
You will note some incredible parallels with the WT. Basically, the catholic church went through the same thing the WT is going through now. History repeats itself.
Oh..don't forget to count 3 hours service time for your phone call! hahaha.