I understand free-shaped icons can sometimes be really bad designed and look really shitty, but one of Apple's distinguished features was their high-quality icons. It was even transmitted to other software companies that target Apple devices. You could tell with high confidence when a software was made specifically for Mac and when it was ported just looking at the icon.
Now everything is this sad rounded cornered square.
My hypothesis is that, at least on VisionOS, some apps are full of — almost cluttered with — 3D objects; and so Apple felt that, for the sake of your eye being easily able to jump to "where the UI is" amongst all that, the user needed to be able to visually differentiate/distinguish action buttons (incl. "buttons that launch apps" — essentially what these app icons are, esp. on the mobile OSes) from those 3D objects. This was achieved by ensuring that action buttons are always button-shaped, rather than allowing them to be arbitrary-object-shaped.
Note that, in this UX-design paradigm, the icon on (in?) a button still can be its own standalone object of arbitrary shape, rather than being forced to be button-shaped itself (see e.g. the Stickies or Game Center icons in TFA.) But that standalone object has to then be "encased" in the "app button" glass (as if encasing something in a puck of pourable resin), to make it visually obvious that this object is functionally a button, rather than just being some random 3D object with its own arbitrary interaction semantics.
Funny enough, this is almost exactly the complement to the problem of visually differentiating action buttons from 2D content. In a 2D UI, you want to make the action buttons more 3D-looking than the 2D stuff around them, to help them stand out. Thus the Windows XP / macOS 9 era of "jelly" buttons with that visually bulge toward the screen — standing proud of the content, affording touch.
But if everything is 3D / stands proud in arbitrary ways, then overlaid actions will stand out better if they're less 3D — making it clear that they're sitting "on the HUD" rather than "in the world." Such objects can be literal 2D — or you can get fancy and choose some unusual middle-ground, like the sort of 2.5D papercut-diorama look that "liquid glass" achieves.
but one of Apple's distinguished features was their high-quality icons
This was one of the things I loved when I switched to OS X in 2007. The Photo Booth, Pages, Preview, etc. were so beautiful. Also very easy to distinguish apps by icons. Now they all look the same-ish.
There was a lot more whimsy as well. The Adium instant messenger had its green bird logo as an icon. And the bird icon in the Dock flapped its wings when you had a new message (this was pre-native notifications, though Adium may have had Growl support already). I think it would also open its eyes when you started the app.
The upside of this 'button-as-icon' interface is that you have a predicable area to hit with the mouse. In macOS of today, if you don't click the area the icon fills, you miss the target. Each icon may have a unique area to hit.
In the days of freeware (pre-App Store "free"), you could pretty well tell the quality of the software by the quality of its icon.
Came here to comment this. Why the obsession with the ubiquitous universal rounded rectangle? There must be some reason these corporations figured out because they're all doing the same.
> Now everything is this sad rounded cornered square.
You see this a lot in the absurd “modernist” design of clean lines, sharp edges, and lack of texture and depth across all industries.
Whether that’s your Thuma furniture where the price is high and your marketed to be told that the design is good, but it’s not at all - devoid of meaning and a sense of place, never mind that the quality of the materials are low and have no specific origin, or your run of the mill drone light show where we are fooling ourselves into thinking that drawing pictures of things like the Statue of Liberty (oh after the drones do the ads, brought to you by your local auto dealer) are good and should be appreciated instead of the vibrancy and brilliance of fireworks instead.
Apple has begun to transition this way too. There aren’t any designers working there. Look at the Calculator app as a great example.
They say perfection is not when there is nothing left to add, but when there is nothing left to take away. But there is a point where you take away more and more and more and your left with creations devoid of meaning or purpose.
Once you start seeing this in your day to day life you can’t unsee it. Sorry ahead of time for those who read this comment and become more attune to this phenomenon.