Micrsoft DirectX has been always the technology driving graphic card sales, but this might change soon. Back in January Microsoft sent a letter to its MVPs saying "DirectX is no longer evolving as a technology. Given the status within each technology, further value and engagement cannot be offered to the MVP community." However, this was later clarified with an official announcement that XNA was being discontinued not DirectX.
Now, adding more support to this suggestion, AMD's Vice President of Global Channel Sales - Roy Taylor has said there will be no DirectX12 at any time in the future during an interview given to a German magazine.