So, you must hate every tech company then since Apple isn't the only one doing this. This is how technology/standards progress, based on prior works. Vulkan is inspired by the work of AMD's standard, Mantel. DirectX is Microsoft's specific closed-source standard and DX 12 came out to be great because of AMD's work on Mantle and so on.
So, you hate Apple's projects, Webkit, Swift, LLVM, CUPS and etc as well? These are standards that did get open sourced and worked out well.
The wording in their docs suggests that APFS might actually be an open source standard.
No, Metal isn't the nail in the coffin. Metal isn't the problem, Apple is. Apple's refusal to adopt modern fast GPUs for their hardware over the past several years is the reason AAA gaming is never going to happen. Apple's continuous demand of light weight and thin designs is what killed AAA gaming.
By the way: some of the graphics engineers said that Metal is actually more friendly to develop with compared to Vulkan but Vulkan is more powerful. Apple has added more features to Metal such as tessellation and so on in Sierra and iOS 10 that should help a bit.
If Apple could just take the stick out of its butts and add TB3 support across all Macs and allow eGPUs, we might actually see AAA gaming return by using dedicated standard GPUs with normal drivers from AMD/nVidia without any interference from Apple.
