You're on HN so you're probably aware of the costs and difficulty involved in staffing an organization large enough to tackle these issues in an effective time frame.

Nvidia has quite a head start. You're not just talking about some simple driver support either. You're talking about runtime compilation/JIT(to target various flavors of HW), tooling support, library optimizations, API stability and maintenance... AMD can catch up, but unless they come up with a new approach it's going to take a long time and a lot of smart people to do so.