I don't want to use MacOS on an iPad screen, I would want to use MacOS on an iPad when plugged into an external screen though. Same with the iPhone. No reason iPhones and iPads of the last few men's to now could not run MacOS on an external screen... well the reason is it would kill low end MacBook sales. Microsoft did this years ago when they had the Windows phone out. Not a great phone but such a fantastic idea, especially for office jockeys who just need a browser and Office. Go to work, computer in your pocket, plug into a dock for power and the screen. Bluetooth keyboard and mouse, work your day out. Ready to leave just pull the phone out of the dock and slide back into your pocket and head out. Small and simple and versatile.