So introduce it when most of the 6600 series stock is gone for a lower price. While there seem to be few models of the 6700 left; a card with more vram for the same money. The 6600 series is still chock-a-block. With 6600XTs and 6650XTs often going for sub $225, and the 6600 $200 sometimes $189, the 7600 value isn't there. That might not be the best deal for AMD and partners, but it is for us.
With the 67xxXT series dropping to $320 it is even more pressure. If you can't stretch the budget, 6600 is the best value. If the prices of SSDs and DDR dropping as they have created new wiggle room in the budget, the 6700 series is the winner. They could not have picked a worse time to launch with a MSRP over $225 IMO. It's in no man's land.
By releasing it now with bad pricing, they generated more negative brand image, and left a bad taste in gamers mouths. If AMD isn't putting their foot in their mouth, they are shooting themselves in said foot.