You are overstating, Cayman is in a slightly worse position than Cypress, and thats the worst case scenario. You know whats a probable better case? Mature 40nm process increases yields for both manufacturers, but AMD yields gain will be exponentially better than massive die GF100b, so AMD even with slightly bigger die they could be in the same position as before.I don't think people are disputing that ATi are in a better position overall. What is being pointed out is that they are in a relatively worse position with Cayman than they were with Cypress. They look like having a similar performance delta but they have a bigger die size.
If we factor supply issue, AMD with all Cypress advantages couldnt benefit fully due to limited supply, its much lesser issue now. UKOC reported they have huge stock already, and it seems its common thing. Therefore AMD could very well profit from Barts/Caymans way more than they could from 5xxx generation.
NV main profits came from pro market, not from consumer division. Plus compare significant market share shift to AMD favor, I guess they took advantage after allATi made the same amount of money over the last year as Nvidia, it was pointed out a few posts back. Which means even with their small die strategy ATi haven't been able to take advantage, which means they have less chance now since they are in a relatively worse position.