When Jobs came back to Apple, there was a similar chaos regarding the Macintosh models. Lots of numbers, letters, and qualifiers, and the purpose of a new model was seldom clear.
He canceled the majority of them -- the "great extinction" of 1998 is plainly visible on the image at https://en.wikipedia.org/wiki/Timeline_of_Macintosh_models .
When it was iPhone 4, 4S, 5, 5S you knew where on the product timeline your phone was. Now it's iPad Air, Air 2, 9.7 Pro, 9.7, 12.9 Pro, mini 4. It's all over the place.