In the latest Bloomberg news Apple is said to be exploring the possibility to ditch Intel processors. This is not the first time such a rumor appears and it could happen.. eventually.
Let's start by considering the "why?" part of the equation. All could come down to the well known control freak nature of people in Cupertino but the decision would really be too big to be guided just by that. Some other things Apple is quite fond of are design and consistency and both may take advantage of a switch to ARM.