I would argue that's not true anymore and I know where you got that from. Yes at one point GNU was most of the utils one would use in a complete Linux system but today just as much if not more is being done by systemd (but obviously nobody would call it GNU/Systemd/Linux). Yes gnu coreutils and libs are the default on most distros and nano is the most popular text editor but I would argue when people think of what makes Linux what it is today they think of the desktops and window managers (so freedesktop/x11/wayland)