Because Preview works, KPDF works and Gview behaved weird or in the wrong way most of the time
Apple builds the automatic car by removing the gear shift, Gnome builds it by removing the gas pedal and just having a button called "Go" which makes you go at 10mph
This means that under the hood, using extensions, you can customize that Gnome car. Can an Apple automatic car do that as easily?
So between the Apple automatic and Gnome "pick customizations" I know which one I prefer (and yes Apple does have extensions, settings, etc). Yes, there won't be a perfect solution and sometimes you kinda miss some minor thing but it is minor.
For example, looking at: https://extensions.gnome.org/#page=2 there's Date and Time formatter (you can do that in Apple) and "Sound Input & Output Device Chooser" which you can do by going in settings in Apple - but it doesn't matter most of the time because the out of box experience works almost perfectly
If I'll ever buy a Mac (and I can't imagine why) I'd want to totally change its windows management and make it as close as possible to Gnome 2 and Windows XP, with virtual desktops (Gnome 2 had them.) I would probably disable all gestures except scrolling and zooming.
I'd also shed tears about the lack of physical buttons on the touchpad but that starts to be about the hardware, which is off-topic.
In contrast, KDE also supports extensions but I've never needed any because it's so configurable.
Which, btw, means that you can never overtake anyone while going up, unless your engine is 2x of the power it'd need with gears.