Rutherford also described a whole group of classes -- Ruth class, Esther class, etc.
If you ask a JW today what happened to all these classes and teachings, you get a blank stare.
If they say anything, it's to mumble something about the light getting brighter.
The real questions are:
-- "Was any of this ever really the truth, or was it just stuff Rutherford dreamed up?"
-- "If it was the truth, what happened to it? Why isn't it important today? Why is it never mentioned?"
-- "Does history show that the WT leadership really speaks for Jehovah God or does it speak the leaders' imaginings?"
These are questions JWs dare not face because they how how much of the WTS' "Bible truth" is simply made up by the leaders as they go along and jettisoned when they decide to go in a different direction.
"New light" is simply a phrase the WT uses to make sure JWs don't formulate such questions or think about them if someone else presents them.