"Perfection" is an irrelevant concept here, but "principled" is not. The reason people favored certain older OS UIs is because they were substantially more principled in their designs, not because the executions of those principles looked a particular specific way.
The Macintosh Human Interface Guidelines, especially the old ones, were seriously well thought out. Apple just doesn't follow them anymore, and that leads to demonstrably poor design choices. "Consistency" is still one of the three banner concepts (see https://developer.apple.com/design/human-interface-guideline...), and Apple just fails wildly at paying attention to itself.
Windows 2000 and Mac OS 9.x.x were contemporary with each other, are both considered to be strong examples of principled interface execution, and they were very different from each other in both behavior and appearance. They were also notably both the last generations of iterative executions of principled designs before both companies started veering off into the wilderness.
The Macintosh Human Interface Guidelines, especially the old ones, were seriously well thought out. Apple just doesn't follow them anymore, and that leads to demonstrably poor design choices. "Consistency" is still one of the three banner concepts (see https://developer.apple.com/design/human-interface-guideline...), and Apple just fails wildly at paying attention to itself.
Windows 2000 and Mac OS 9.x.x were contemporary with each other, are both considered to be strong examples of principled interface execution, and they were very different from each other in both behavior and appearance. They were also notably both the last generations of iterative executions of principled designs before both companies started veering off into the wilderness.