Currently the engine developer in graphics programming writes something and in reality he has no way of knowing what actually happens on the hardware (the API is just too high level to able to really know much). From there it is the hardware providers job to take out their own debugging tools and make sure correct things happen by having a custom code path in the driver.
Lower level APIs like DX12 and Vulkan remove the competitive advantage vendor dependent performance creates, so well-coded games can perform consistently with lower overhead across ranges of hardware without having to rely on vendors to patch in the shortcuts through their drivers.
Currently, it's like filming a movie with IMAX specifications, then finding out that at different cinema chains it played with quality aberrations because their projectors didn't truly follow IMAX spec. The chains can fix it, but you're already getting blamed for the movie's issues. However, for a little money, on your next film they offer to work closely with you to ensure it shows the way you intended in their theaters. And no, they can't just tell you how to fix it-- their projection technology is a trade secret.
Games Studios, IMO, should be made to fix their bugs themselves. They all have patching mechanisms these days, so it's not like it isn't impossible, or even unfeasible.