It does not matter how mutch it gives them back, the camp that dont offer it is the one that looses this time in the long run and the way games goes 2GB/core will be a nessecity even at lower resolutions, this is not due to "bad porting/bad optimization" it is just the way it goes right now.I would say "money is no object" for so few people it doesn't generate much revenue for either company. In the grand scheme of things, a tiny fraction of people will buy 1 of these cards, let alone 2.
Only reson why 5870 sells besides the e-penis are the lack of competion in the DX11 area that is not even usefull yet. You would be amazed how many that planing getting 2 of these cards.