Jeff,
I agree with your thinking.
WT is a manufacturer currently without a product to offer. I'm not necessarily talking about paper magazines and books but more about information to be printed or published electronically.
WT previously had Fred Franz to spout out an abundance of new doctrine. JWs were excited to receive new books and new understanding every year.
Apple doesn't release a new iPhone every year because the existing model isn't selling or isn't reliable. A new model is released so that existing iPhone users will become excited and buy a new phone to replace the phone they only just purchased last year or the year before.
Without new original doctrinal ideas, WT has nothing to excite existing JWs.