Who knows If apple does well with those kind of "universal Programms" we might see developer start to get more interested in Apple and the Mac especially. Imagine having the possibility to bring your Game to the iPhone iPad Apple TV and the Mac without having to create different versions for them.
Apple Tv might be strong enough in the next generation to compete with something like the Switch. Ipad Pro and Iphone will get insanely fast. If apple would make sure to create some good gaming peripherals for all of those Platforms Metal might be a strong possibility for the major Game developers.
Also Sony would look pretty badly if this happens. Microsoft has Xbox and Windows (Tablet, PC and Console) Apple would have IOS TV OS and Mac OS ((Tablet,Phone, PC and Console) and Sony would rest with their one platform which has to compete with Nintendo and Microsoft.