One thing one can take note of is that the WTS never had any true academically trained bible theologians, starting right back to C T Russell. (late 1800's)
The men that took over from him such as J Rutherford were Biblicaly trained by Russell an novice if you will who he himself drew in other theological concepts from others the like H Barbour and C Symth where Pyramidology originated.
The long list of the top leaders of the WTS were essentially trained and indoctrinated by novice bible theologians, Fred Franz to name another, nevertheless these men had a publishing house in operation and they were pressed to make their doctrinal teachings attractive to the open public, hence this why and where 1975 came about.