Mac OS and iOS are becoming more similar with each release. I believe we'll reach a point where the operating systems serve such a congruent experience that they'll converge to become one, especially as it can no longer be said that a consumer needs a full-blown computer for a smooth experience or professional-grade performance. Similar to the switch to Intel from PowerPC, eventually I foresee all manufacturers switching over to a mobile architecture. I do believe in their quest to make devices as thin as possible all Macs will include AX chips, providing incredible battery life and form factor. This may not even come in the next decade, but I believe iOS will down the line effectively replace Mac OS as they become one.