If the only justification for the $550 pricing was that it was faster than a gtx 580, that a horrific excuse and completely justifies the current turing pricing which looks great with the midrange cards filling out the lineup. It also makes Nvidia look like saints for the pricing of pascal.
The GTX 580 was a huge monolithic 520mm2 die and a completely different die class than the 7970. Just as importantly, it came at a time when new wafers were largely static and cost per transister was still decreasing(28nm).
If the only requirement for pricing is performance and not cost to build, then turing pricing is okay(atleast as good as 7970 series was, probably better) and pascals was downright Nvidia giving away their products away.
The 7970 and the 7870 was priced in a manner where there was essentially zero improvement in terms of price to performance much like turing. This is why we saw such a great increasing in pricing for videocards for Turing if we go by 7970/7870 logic. As long as a card is faster than the generation before it, it can be priced the same or higher. Atleast Turing has the die size increase, Nvidia brand and lack of competition response for 10 months going for it. Look at techpowerup charts for price to performance and the relative pricing and positioning and they are in the same spots.
The 7870 was probably the more egregious offender because it was a mainstream part given high end pricing(not enthusiast). Looking at the 350 dollar pricing vs cards like the rx480/gtx 1060/GTX 1660 ti and the fact that it was made on cheap 28nm just shows you how much AMD was trying to fleece customers. It was a 213mm2 die, that had the same price to performance as 520mm2 die(at initial MSRP, not dropped street pricing) in the form of the GTX 570.
So what happens when a company only takes into account performance and not any potential savings in BOM, we get the pricing we get today.
However 7970/7870 pricing was done in a manner where AMD the sword of Damocles was hovering over them which ultimately made it a stupid move in the long run.
What made the 7970/7950/7870 pricing stupid and greedy unlike Turing which was simply greedy was the AMD brand, the time line of the competition to arrive and the die sizes.
Keplers launch was only 2 to 3 months away. The high pricing of AMD 28nm made a lot of people wait on the fence on top of the mediocre increase in performance compared to the 5870 series on top of the price increase. This was on top of the AMD brand enhancing all these risk factors because consumers are more hesitant to spend money on AMD at premium prices. Ultimately this bet did not pay off and AMD lost.
The price AMD paid was a gigantic loss of good will built up as AMD fans even bought Nvidia, helping the competition look like heroes and having to price their cards lower with price drops and free games to the extent it was selling below what a fair initial price would have been. (Drop from $550 to 399 + 3 free games). The GTX 680/670 looked like king kong by taking the price/performance/efficiency on top of the Nvidia brand. The consumers paid a high price as well with increased pricing across the board. Pascal
In comparison, pascal worst value, the GTX 1080, brought 20% extra performance vs the GTX 980 ti for 599/699(essentially no increase in pricing) looks terrific vs the 7970. The GTX 1070's 399/449 pricing for performance 5% faster than a gtx 980 ti looks downright nobel peace prize winning compared to the 7970/7950/7870 when we look at the GTX 980 ti's $650 dollar pricing. Combine this with the cost of finfet and perhaps we should give sainthood to Nvidia. Sarcasm aside, it just shows you how prosperous the pricing of the 7970/7870 was and why it accelerated pricing so much for consumers.
Turing pricing simply goes along with 7970/7870 pricing logic(priced without improving price to performance for consumers) without the risk factors like eminent competition arrival and the Nvidia brand.