If anything the current crop of new graphics APIs (Metal, Vulkan, and DX12) all owes their start to AMD's Mantle project. Metal certainly didn't get the ball rolling, although it almost certainly accelerated Khronos's path to standardization & shipping (which is why Vulkan adopted Mantle as the base, to ship quicker). AMD gets that claim.

OpenGL was not stuck, either. OpenGL's AZDO project was alive & well: https://www.khronos.org/assets/uploads/developers/library/20... (just not on macOS because AZDO is GL4.2+ whereas macOS is stuck on 4.1)