You know this, but among others Werbos (dissertation 1974, the one you were building on) would probably raise an eyebrow at your "earliest" assertion :)
NN have been cyclical for decades now and I expect they'll cycle again.
You are right. I got caught in the wave of excitement after the Rumelhart, McLelland and Hinton PDP book chapter of 1986. But as you say, there were a lot of things that had already been done in NN going back to perceptrons. My first exposure to neural networks was in 1987 in Byte magazine of all places. There was a great article by Bart Kosko on associative memories.
NN have been cyclical for decades now and I expect they'll cycle again.