They have patents on a lot of stuff. I think cut and paste was one but memory might be off. They use patent suits to suck billions out of Android suppliers. We'd probably have seen that with Windows-compatible desktops like ReactOS if they got mature enough with enough users.

Further, Oracle going for the API ruling means companies like them could monopolize at API level by making ports even riskier and costlier. Then, there's the interface look-and-feel which Apple likes suing over. That's at least three ways they can go after competitors.