It's a shortcoming of the software. Apple could claim it's a third-party issue if they didn't support arbitrary external monitors, but they do. As such it's ent

It's a shortcoming of the software. Apple could claim it's a third-party issue if they didn't support arbitrary external monitors, but they do. As such it's entirely reasonable to expect a fallback solution for third-party displays that Just Works. For my money, Windows is a terrible operating system but it embarrasses Mac and Linux thoroughly in this regard.