That's easy: not everyone agrees they're regressions.
Also what are the problems being solved by these redesigns and rearrangements? What was solved by going flat in 10.9 -> 10.10? What was solved by going even flatter, and using the dreaded SF Symbols icons everywhere, in 10.15 -> 11.0?
It's a done product — it's been one for quite a while. Could they just stop meddling with the UX already and maybe rewrite their PDF parser in a memory-safe language instead?
I find I legitimately prefer the newer UI of Big Sur onwards. I just don’t feel the need to shout it from the heavens.
An alternative take: you’re really going to suggest that one of the richest companies in the world doesn’t do extensive UI/UX testing before putting things out the door? They’re not just saying “yeah, this looks nice - ship it!”.
A good UI designer makes buttons look like buttons so our brain can quickly recognize them as such, without mistaking them for something else. A good designer has the window title in the same place no matter the application, so we know where to look before we even look. A good designer gives us a place to reliably perform common actions such as dragging the window.
We use our computers daily, and even imperceptible improvements to cognitive load and the amount of time it takes to perform actions make a difference over time. When I use my 2009 iMac running Snow Leaoprd, I perceive a reduction in friction compared to the latest macOS versions, and even compared to Catalina, which I use as my primary OS.
I have 20/20 vision and I had to turn on contrast and button shapes, the new design is so bland and unreadable.
Macs have large screens and that's why... they changed all dialogs to be tall narrow boxes with center-aligned text?
Properly labeled color-differentiated icons are now indistinguishable grays crowding the title bar removing all affordances (from being recognizable to being able where you can drag the window).
Keyboard access is being removed or broken across all first-party apps.
Desktop metaphors like multiple columns, tabs etc. are removed in favor of tall narrow strips of gray text that surely look great on a screen that fits your palm. But that's not the screen Mac OS operates on.
The new designs break Apple's own HIGs and other recommendations like WCAG.
So please tell me what it is you like about new designs and, more importantly, what the hell is their purpose?
Can't wait for this. And the same for the e-mail app. Even just a Swift rewrite of the 'hairy' parser code would be a reasonable starting point.
Why are people so eager to go back to a system where you have to hire an artist who knows how to make 1000 inner bevels so you can have any custom controls or app icons?