Because, with a few tweaks here (going from 16 tmus to 32) and few changes there (850 core, 1050 shader) its a different animal thats also as cheap as their old cards, which were competitive, but not on the same level. The 2900 came out at a mid-high price of 450$, which was not good enough because it couldnt topple a card that was already under that price (8800gts640) This time, word is that its different, real competition has about to hit. This is great news for all, except the green fanboys, but even some of them are tired of what nVidias been up to lately