Nothing. And that is the problem. When you are generally speaking doing everything well there is little room for massive improvement. The days of perpetually exponential improvement, and resulting growth, are over. Apple is not a startup. Like Ford, Sony and GE, they now have to settle into the grind of incremental improvements for reasonable returns.

Or they can put their markers down on ever more grandiose schemes. They could branch into transportation by starting an airline, or a robot taxi service, but I doubt shareholders will tolerate such outflows for long. If doing so causes the neglect of the core business (iPhone) shareholders will revolt.