Although they created and gave OpenCL 1.0 to Khronos, they were not happy with the path that Khronos was taking it and their support basically stagnated on OpenCL 1.0.
As side note Google is yet to support OpenCL on Android, instead just like they did with their Android Java, they decided to create their own flavour, Renderscript, which isn't compatible with OpenCL.
As for OpenGL ES, I bet they only did it, as they were trying to "play pretend" being another kind of Apple as survival mechanism, nowadays they don't need it any longer.
Finally, Metal is one year older than Vulkan, offers a modern API instead of plain old C, and contrary to Khronos, just like other platform vendors, Apple understands the value of providing nice frameworks and debugging tools to go along an API.
You should have a look to pwcalton's Twitter feed if you want a quick overview of how nice the tools in questions are. Getting a kernel panic when running Xcode doesn't sound like “nice debugging tools” to me…
Is it really though? Vulkan is based on AMD Mantle which AMD gave to Khronos. AMD Mantle (2013) predates Apple Metal (2014).
When Apple released Metal, Mandle was still an AMD API.
I'm not talking about pre-NeXT Apple, that's ancient history.
Many just don't realise how they were fooled to believe in the wolf in desguise.
Corporations do whatever to save themselves.
Do you think Microsoft will keep being FOSS champion, after they wipe out the board?
How naive are those that assign human behaviour to corporations.