You're exagerating the similarities between the two systems. Besides, isn't OSX based on Debian Unix? Surely this is a more blatant example of borrowing from another OS (note that I don't call it stealing, because, obviously, it isn't) than Microsoft using certain similar design concepts to OSX?
If you are saying that OS developers are only allowed to learn from and build upon their own previous operating systems (which your argument basically seems to boil down to) then should Apple remove all traces of Unix from OSX? Or does this "no copying" rule only apply to Microsoft and their products?
If you are saying that OS developers are only allowed to learn from and build upon their own previous operating systems (which your argument basically seems to boil down to) then should Apple remove all traces of Unix from OSX? Or does this "no copying" rule only apply to Microsoft and their products?