Apple love to preach "the UI gets out of the way of your content" with each new redesign, but how true is that in practice? Let's compare the total height of the Safari UI with a toolbar, favourites bar and tab bar visible, across the three latest Mac OS design languages – Yosemite, Big Sur and now Tahoe. I've added a red line for emphasis.
It sure looks to me like the UI is eating more into my content with each redesign.
Leopard and Snow Leopard had vastly better virtual desktops than Lion onward. You actually had a grid of them and could navigate up/down/left/right with shortcuts; afterwards you only got a linear list of desktops.
Gridded desktops were great. I had a 3x3 grid, of which five cells were used. My main desktop was "centered". Thunderbird was right. My IRC and IM clients were left. iTunes was down. I don't remember what was up; it's been a while.