I think the answer to this question comes in the arrival of J Rutherford fighting struggle of the take over of the WTS.
Corporation. That personal take over created a power structure within the organization that wasn't there before under
Russell. He disregarded Russell's own Will and started to publish his own books and pieces of literature penned by himself.
While the organization slowly grew in public support, at the same time more illusionary power grew within the heads from
such men as J Rutherford. More and newly devised doctrines were created out of that psychological delusion of power,
which eventually created the religious organization that exist today.
C T Russell was more concerned and focused about literature distribution which his publishing company was producing
and printing and as a vital means to express his own religious ideologies which in actuality were mostly not of his
own creation.
So readership was Russell's core agenda where Rutherford was also concerned but he added
something else and that was absolute power and control as the organization's leader.
Remember he was the one who in 1919 came out and stated that god himself has selectively chosen the WTS.
organization as its earthly spirit directed organization.
This growing self perceived power grew from there and continued on to what appears today with the WTS.