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.
Speaking as someone who works with two 32” 4K displays, if you want to run them at a decent resolution, the buttons, text, tabs, and everything else become ridiculously tiny—so much so that it almost defeats the point of having large monitors in the first place. You’re stuck squinting and making precision mouse movements just to hit these microscopic UI elements, and you can’t resize them without lowering the entire display resolution.