So you admit that your 'less than one year' point was de facto phoney?OK. Now apply that “normal to discontinue” implication to the 6s and 7 still for sale in the Apple store, with the 8 long since available.
You treat every deviation from the norm (Apple keeps the same model around at a reduced price in their second and often also third year of their existence) as only being explainable by poor sales. Well, we expect to have a second deviation from that pattern in September. The first deviation obviously wasn't because of poor sales (of the iPhone 5) but that doesn't stop you from saying that poor sales are the only explanation this time.
Ignoring completely that quite a number of things were already different in this cycle. We got three new phones last September (and not just the same kind of phone in three different sizes), one of them being significantly more expensive. The next cycle again looks to be different (sure, an iPhone X.2 and a X.2 Plus, but also a 6.2" LCD one), plus the iPhone X.2 is rumoured to be a bit cheaper. So, many things are different from the longtime pattern, but again, to you only look at one of the deviations (iPhone X only being sold for a year) as if all the other changes in the lineup weren't happening.