AMD's prices are a result of nVidia's announced AIB price. A GTX1070 will be so much better that there wasnt any room left for AMD for a product over $250.
Provide a source or this is your speculation.
All logic would indicate this is an absolutely ludicrous theory. 1) Product planning for an ASIC starts 3-5 years in advance of launch. 2) Your theory assumes product planners at AMD had no target market, no target price, no target cost, no target margin, until ~6 months ago when nVidias prices were available.
What's more likely: your theory is wishful thinking, or AMD didn't have a target market or price in mind when they decided to start designing at ~200mm2 die 3+ years ago.
Yeah you're probably right though, the AMD planners just threw darts at a board to decide die size and price 3 years ago and now they're scrambling because a billion dollar multinational corporation doesn't think about target markets before designing products.