Yep Amiga was five years dead before OS X came along....
Yes, but OS X is just repackaged Mach (with display PS instead of X11), which is a flavor of Unix, which dates from ... you know the story.
One of the exciting things about the Amiga, as Carl Sassenrath has stated, was the complete break with *nix tradition and philosophy. As I was using unix on workstations at the time , I agreed, and still do, even though I have to type this on one of those OS XMach thingies.