So what? Thats not MacOS.
I think things are fine on iOS. I don’t mind the rectangles, they fit the grid. That’s how it’s always been.
I don’t care about VisionOS. Circles are odd, whatever.
But the Mac shouldn’t be forced to lose great design because iOS was under different constraints almost 20 years ago. That’s just dumb.
They were trying to make a unified design language across all their operating systems. If iOS and VisionOS both have their icons sitting on uniformly shaped tiles, macOS would break the convention.
I don't like it, but I believe that's the reason why.