Metal does pre date Vulkan, and some people consider it easier to use.

While Metal might be easier to use, i'm pretty sure it is still easier to have to worry about Vulkan alone than Vulkan+Metal. And Metal predating Vulkan is really only of concern to code that existed before Vulkan was made available (which wasn't that much).

OpenGL is easier to use than both, but we left it in the dust as it doesn't match the semantics of modern hardware.

Metal DOES... but only apple hardware.

Well, ya, it's a proprietary walled garden solution.

Mantle predates either, and Vulkan is based on Mantle.

Vulkan is not supported on game consoles, with the exception of Switch, and even there you should use NVN instead.

It is not officially supported on Windows, it works because the GPU vendors use the Installable Client Driver API, to bring their own driver stack. This was initially created for OpenGL, and nowadays sits on top of the DirectX runtime.

On the embedded space, the OSes that support graphical output many are stil focused on OpenGL ES.

Vulkan capture support on Windows was introduced in v25 (on linux you need to use a plugin). There is no Vulkan renderer support—which the post clearly stated...

As if nobody else ever did that (like Microsoft with DirectX, and almost every single games console)?

Sure, it's happened before but it is not in Apples customers interests, just Apples corporate moat building interests.