This is an unlikely rumor from an unknown Twitter account: Apple is reportedly working on a version of macOS that will run on the iPhone. The objective, according to this rumor, is not to have macOS on the screen of your smartphone, but rather to transform an iPhone into a computer, with a screen, a keyboard and a mouse. Just like Samsung tried to do it a few years ago with DeX:
It is not so much the rumor in itself that is interesting, but more the underlying idea. Now that the Macs will switch to Apple Silicon processors very similar to those of the iPhone, Apple could very well adapt macOS so that the system works on an iPhone. It would probably require some adjustments, if only to manage a lower amount of RAM, or else it would require new equipment better equipped. But in itself, there are probably no major technical limitations.
It’s not because it’s possible that it’s a good idea, however, and DeX experience has amply proven it. Really imagine that you can have macOS or iOS on an iPhone, you would have to switch from one system to another and wait for the startup time. Even admitting that Apple manages to keep the two systems on standby to accelerate the transition from one to the other, also admitting that all data sharing problems are completely resolved, what would be the point of having a such a complex system when there is a simpler solution?
iOS and iPadOS are already capable of managing an external screen, keyboard and mouse or trackpad. Admittedly, the system continues to duplicate the display of the device by default, but this is a point that could be raised more easily, if Apple wanted. It wouldn’t take much to have a function equivalent to DeX with the simplicity of having a single system to manage.
In short, macOS could certainly run on an iPhone, but will Apple ever do it?