I think the general consensus is that quite a bit, but maybe not ALL, of the Apple Copland demo videos were either faked, or extremely carefully edited and modified to look correct. What's definitely the case is that the versions released to developers did not look and absolutely did not function like what was shown.
I have d11 on a 6100, and it only has the platinum theme, and there are no animations at all. The theme itself and even the font are subtly different, but extremely close to what we got in MacOS 8. See
https://macintoshgarden.org/forum/writing-software-copland for screenshots of my machine running it, including software I wrote (just standard Mac stuff, that took no advantage of anything new in Copland).
It looks like d7 had the Gizmo theme
https://www.youtube.com/watch?v=FoVEZb2ropk but he doesn't go to a menu in the video so we can't see if there were animations. BTW, d11 is much more stable, and not QUITE as terrible as what the guy goes through in the video, but still very very fragile and goes to the debugger constantly, needing reboots after running just about anything.
I really should install d7 or d9 on my 6100, always wanted to, just to see, but at the same time, have spared myself the grief and pain of doing so.
One strange thing is d11 is actually missing a bunch of things d7 or d9 had. They probably left them out because they didn't want people trying them, and having them fail, wanted them to focus on what actually worked.
There were sets of include files distributed with the Copland Developer releases. I think I remember seeing one mentioning "Desktop Animations". I might be able to dig them up. Regardless, the concept was definitely abandoned and never made it past Copland.