You are comparing apples with oranges here. Metal and OpenCL are different technologies. OpenCL is cross platform and an open specification while Metal is used only on macOS and iOS.

What makes you think Metal has been dropped?

Ideas that dumb can only last so long. I hope.

Apple has no market dominance in the graphics/compute domain and they want people to spend time and energy porting to a locked-in proprietary API when they haven't even had success getting people to use cross-platform open APIs like OpenGL/CL? Madness.

Are you kidding? Metal isn't just on macOS, it's on all of Apple's platforms. With the iPhone alone they have all the market power they need.

I have OpenGL code running on FreeBSD, Linux, MacOS X and Windows. I'm not going to write a second implementation for Apple systems. Vendor-specific graphics APIs are a throwback to the '90s. I am categorically not going to support Apple's Metal API; they need to bear in mind that much software using OpenGL is not Mac-specific, and given the poor state of Mac graphics Macs are decreasingly a second class platform for serious graphics use. Even FreeBSD has better OpenGL support(!)

"Market power" is fairly meaningless when you support multiple platforms. Most games ported to Apple platforms use OpenGL; using Metal would restrict their market significantly. And expensive high-end software has better support on platforms where you can use expensive high-end GPUs and compute, and that's not today's Apple hardware. Metal is a non-starter for a very large number of people, and they need to get their OpenGL and Vulkan support up to par or many of us will cease supporting Apple platforms entirely.

This is shortsighted attitude that, in the long run, will be toxic for Apple. It's one thing to not give developers what they want because you can't ( doesn't fit the technology or the product, don't have the resources or whatever). It is quite another to do that simply because you won't (e.g. for strategic lock-in reasons).

Yes, the iPhone gives them all the market power they need with some developers, even many devlopers. But others don't care about the iPhone for various reasons. Those developers, grumble, moan and eventually buy computers that aren't Macs. And when those developers make great things they're outside of Apple's ecosystem, encouraging other developers and customers to leave it as well...

They've already lost a lot of high end UI, video, and game developers. Pretty sure they're going to lose the mass market audio developers on this android release. I guess audio latency is good enough now for many audio apps... and that's where all the users are (well, in a year after upgrades they will be). A lot of the existing apps have updated to use the new low latency APIs.