Says who? Why?
It looks long term stable to me so I don't see the issue.
No current gen console supports it. Mac is stuck on OpenGL 4.1 (you can't even compile anything OpenGL on a Mac without hacks). Devices like Android run Vulkan more and more and are sunsetting OpenGLES. No, OpenGL is dead. Vulkan/Metal/NVN/DX12/WebGPU are the current.
Edit: By the same logic you could argue that C89 is dead for new projects but that's obviously not true. C89 is eternal and so is OpenGL now that we've got decent hardware independent implementations.