ISV had years do to this, and when porting the first time did this for macOS-only anyway (Windows uses DirectX). Moving from OpenGL 2 to OpenGL 4 would have be

ISV had years do to this, and when porting the first time did this for macOS-only anyway (Windows uses DirectX). Moving from OpenGL 2 to OpenGL 4 would have been just as much work as moving to Metal 2.