It’s not whataboutism, it’s personal experience. I used Slackware mostly after switching, so no Gnome.

About significance - you might be mixing up Gnome 2 to Gnome 3 transition with GTK2 to GTK3 transition.

GTK3 I hated with passion, oh yes. I literally built GTK programs from source if the repo version was GTK3 and GTK2 was supported for some time period, later got too lazy to do that.

Still, the inconvenience of needing a whole theme instead of one ~/.gtkrc-2.0 file .