Eh? Theming was fizzling out by 2005, which starts to correspond to the rise of OS X and Macbooks.
Enlightenment came out in 1997 and was all about theming. But theming predated E by a few years already. https://en.wikipedia.org/wiki/Enlightenment_(software)
This is what I would call the "golden years" for Linux theming. Late '90s to early 2000s.
> Windows look and feel was never really a thing, nor was theming because of the same thing.
I mean. Did you even read the article you're commenting on? Windows 3.11 had themes. Windows 95 had Microsoft Plus: https://en.wikipedia.org/wiki/Microsoft_Plus!
> Then GNOME 3.0 came and they went for the consistently branded experience approach
This happened way before GNOME 3 was a thing. GNOME 2, Xfce, and others stopped their obsession with Windows and started thinking about OS X, which was eating the desktop UNIX lunch.