That's exactly what companies do when they are faced with "companies of greater than size N must follow extra rule" regulations, although many here will say that is just cheating.
I'm going to have to ask for a source of this claim that people who want antitrust action against hypercorporations would somehow be dissatisfied with the stated goal of antitrust, which is to break up trusts.
The sucess of iPhone/mac/icloud doesn't really factor into it (some of them will shrink and some will do better as they're not subsidizing other parts of Apple or can canibalize other parts of Apple's market). You'd be right in asserting the success of Apple is a factor, as those who are arguing for such a seperation would say, it's making outsized profits by not competing fairly in several of the markets it's in.