They don't they pay developers to make them run well on NVidia cards, ATI just expect developers to do all the work for them.
This is rubbish, the same few Nvidia people just try to give the impression AMD don't care, or try.
Its fairly simple, Nvidia had the bigger market share, far more money and could pay for both more support staff to send to these companies and more money to pump into the developers.
Fact is when Nvidia give a developer a couple mil to support their game more, to let their programmers help "optimise" the code for their hardware, its not that AMD don't try or expect anything, they didn't have the money to pay as much as Nvidia did and its that simple, cash, Nvidia had more and bought more titles.
AMD has for years had teams out, but if Nvidia are paying dev's for 2/3rds of the main games coming out in a year, is it worth AMD having a team twice as big as Nvidia's to sit around and do nothing all year? no, its a business, no one throws money away and Nvidia's money brought with it good returns.
But the end of the day developer "relations" was nothing more than whose the bigger spender.
Nvidia profits have tanked, Nvidia's team has been reduced and their spending cut, and quite obviously the number of games they've been involved in has been cut aswell, with several fairly high profile titles being taken over(and improved quite significantly) by AMD's team.
As more dev's aren't bought by Nvidia, theres more room for AMD to work in, and more money for them to spend.
As for Rroff's claims they would do the same, other than AMD specifically stating they would never do so, PUBLICALLY, unlike Nvidia, they've not locked ANYTHING out in multiple titles they could have already.
Is DX11 not working in Dirt 2 for Nvidia? no, do any of the main dx11 games block a single feature out from Nvidia cards, no. So really theres your proof right there.
Most of what Nvidia do isn't "nasty" but paying to optimise for their hardware, fair enough, except when it blocks out developement on other platforms its more of a grey area/borderline wrong but not type situation. As for blocking known AA paths, crippling THEIR OWN HARDWARE in the presense of AMD cards, well, that is nasty, wrong, entirely stupid and frankly, petty as hell. The disabling Physx when an AMD card is present is amongst the dumbest things they've done of late. Considering the bad feeling and multiple reviewers commenting on its stupidity, while encouraging zero sales due to the timing(5xxx series spankingthe gt200b and Fermi not being out for months) and the complete lack of must have physx titles that might have persuaded people to pick up a high end Nvidia card over AMD, it was just petty and hurt them more than it helped.