ATI gave Valve $2.4 million in cash for the deal. ATI also invested $1.2 million in marketing this great game. And last, but not least, was a cool $4.4 million that ATI and its partners spent for bundles.
That amounts to some $8 million dollars. This is a lot of money, I can agree, but ATI never sold so many mainstream and high end cards in its long history as when it bundled them with the justly famous voucher. It sold an incredible lot of 9800XT and 9600XT cards just because of the nice voucher. That small piece of paper convinced many people to go out and buy ATI card.
ATI actually benefited from HL2 being late. People were just buying and buying ATI cards because of the voucher and just to get the free game. So it was a win-win rather than a whinge-whinge deal for ATI, which recouped the money back from end users.
As for Nvidia, we can surely bet that Nvidia spends even more on its highly successful TWIMTBP marketing program, but Nvidia invests in many games and not in a single game only. A chapter in the history of vouchers has just ended. µ