Gaming

It's super easy to forget but Ubuntu tried to do it back in the day with Convergence as well, and amusingly this article also compares it to Microsoft's solution on Windows Phone. It's a brilliant idea but apparently no corporation with the ecosystem to make it actually happen has the will to risk actually changing the world despite every company talking about wanting an "iPhone moment"

Apple would be in a prime position, they’re entire ecosystem is now ARM based and they have the chips with enough power. But it’s not their style to do something cool to threaten their bottom line. Why sell one phone when you can sell phone, laptop, tablet, desktop separately?

Let's be real, Apple's biggest risk would be losing the entire student and young professional market by actually demonstrating that they don't need a Mac Book Pro to use the same 5 webapps that would work just as well on a decent Chromebook (if such a thing existed)