Software licenses still work exactly the way we've always thought they do if the federal circuits ruling is shot down. Copyright still works exactly the way we've always thought it done.

No one has ever thought that you could stop people from copying APIs. If they did all sorts of things like Linux (hi Unix), Wine, Windows Subsystem For Linux, AMD x86 CPUs (ok, Intel might have licensed them to avoid anti trust issues), Intel x64 CPUs, and so on would not exist.