People really have to get away from thinking of these medium cards and the really big cards as part of the same line up. Maybe they were 5+ years ago.
Now, no. NVidia have a rolling, annually refreshing (at an absurdly regular +30% increase/year) line up of GFX cards. The fastest card at a given time alternates in size between big and medium but has a roughly fixed price.
The 1080 is at the top of the 2016 line up.
I get the point that you're trying to make, but please try to understand mine.
From the German link above they argue:
"Damit bleiben noch einige Fragen offen, welche sich dann aber erst mit dem Auftauchen der Herstellerdesigns zufriedenstellend beantworten lassen. Dazu gehört auch die allerwichtigste Frage diejenige nach dem Preis/Leistungs-Verhältnis. Eine Antwort hierauf kann derzeit nur sehr eingeschränkt gegeben werden, da die Herstellerdesigns fehlen sowie zum Referenzdesign der Founders Edition nur Listenpreise vorliegen, aber noch keine echten Straßenpreise. Davon ausgehend, das sich die nVidia-Vorgabe von 789 Euro tatsächlich so im deutschen Einzelhandel zeigt (der US-Listenpreis würde direkt umgerechnet eigentlich eher ~735 Euro ergeben), kostet die Karte gegenüber Radeon R9 Fury X und GeForce GTX 980 Ti ziemlich exakt so viel mehr, wie viel sie auch mehr an Performance erbringt. Dies ist oberflächlich in Ordnung, normalerweise bezahlt man für Spitzenperformance gern auch einmal klar mehr als was es an Leistungsschub gibt."
My courtesy translation as a native German speaker will be: it's normal to pay for more performance, and the 1080 brings quite a bit more performance than a 980 Ti and a Fury X. Fantastic - generation X+1 produces graphics cards faster than those in generation X. If your argument (and the one from the website) were extended, it would follow that graphics cards continue to increase in price forever (with each generation). The 'buying now' element that you cite in your post about timing (that this will be the fastest single gpu card in 2016) is simply timing manipulation by a company to try to get as much money as it can for products that it wants to time right - milk a bunch of money from (legitimate upgraders and those who want more but don't want to wait much longer) and prolong the 'need' element so that someone like me would upgrade repeatedly.
They are free to do that - businesses exist to maximise profits and to survive as long as possible, but I am also free to call them out on it. Buying a 1080 for something like EUR 800 is a joke, considering where it sits in Nvidia's product lineup - which they should not release if they themselves don't want us to see the card as anything more than stopgap milking. Was there anyone happy they bought a 980 over a 980Ti? I doubt it.
Did anyone pay as much for a 980 as a 980Ti? I'm not sure - potentially the day the 980 was released?