Well they have an OS already which unites them, the API layer above is the heterogeneous bit, which they might unify with something like UXKit. Long term it would make sense, and as you say it would explain the move towards mobile paradigms on desktop and the relative neglect of the desktop software. Of course the other explanation is that there is just so much more money to be made in consumer electronics than in computers - that won't change.

I expect Apple under Cook to be far more predictable in this way and take the steps to maximise revenue that Jobs might have shunned in favour of something revolutionary and unproven.