In contrast to matthewmacleod, what I find tenuous is the argument that these things would have been open source if it weren't already so and these had been initiated from within Apple instead. Case in point: Swift!
To be fair, if Apple had developed their own printing system instead of using CUPS, it probably would have been highly integrated with/specific to OSX and never would have been open sourced.
In contrast to matthewmacleod, what I find tenuous is the argument that these things would have been open source if it weren't already so and these had been initiated from within Apple instead. Case in point: Swift!