The early 80s were an era where it wasn't even entirely clear under US law that software was copyrightable. Franklin didn't attempt to demonstrate that they'd independently come up with equivalent code. They didn't attempt to demonstrate that the extent of their copying was to ensure compatibility and no more. They merely asserted that an independent implementation was impossible. Their defence was effectively "Yes, we did this, but we should be allowed to do this". It was worth a go at the time, but it's not really terribly surprising that it ended the way it did.
But that's not equivalent to copyright arguments over an API. Apple v. Franklin never really determined whether or not an API was copyrightable - it merely decided that object code *was* and that Franklin had directly copied Apple's object code. It's even indicated that third parties had produced compatible code without direct copying, but that Franklin had simply chosen not to.
I don't think this case covers anything relevant, other than indicating that courts are able to change the status quo. Before this and the Williams case, the assumption was that software might not be copyrightable. It's conceivable that Oracle might trigger a change in assumptions about whether APIs are copyrightable. We just have to hope not.