I didnt say that *no* developer would use mantle without being paid, i'm saying it just doesnt make financial sense to when the target audience is less than 20% of your customer base the likely "extra" sales from mantle support is unlikely to cover the development costs, so it doesnt make sense to do so... that doesnt automatically mean that no one not being paid by AMD will support it, but it makes it a lot less likely than if AMD had stronger market share and better backwards compatibility
what is the % target audience of dx12 then?
what nvidia/AMD GPUs will support it?
What OS will be supported/locked out?
just saying its not as if dx12 is going to launch will a huge catalog of games and support from the start. How long was it before dx10/11 became the norm?