think their problem goes back to Rutherford who changed Russell's policies and put the emphasis on preaching and increasing numbers rather than on character development in other words on quantity rather than on quality and the JWs are paying the cost of this policy until now.
I recall reading coc by Raymond​ Franz back in 2002 where he mentioned how Nathan Knorr appeared to be fixated on numbers also. I think they were traveling in a car and listening to the radio about how many had attended some famous preachers convention locally( think it might have been Jimmy swaggart); and Nathan Knorr made a comment about the numbers and gloating that the Society drew bigger crowds to their conventions.
It is interesting that Ray Franz felt uneasy about this attitude too ie 'quantity over quality'