They do, but their resources are fairly limited so the methodology is abysmal. See https://blogs.gnome.org/shell-dev/2021/02/15/shell-ux-changes-the-research/ h

They do, but their resources are fairly limited so the methodology is abysmal. See https://blogs.gnome.org/shell-dev/2021/02/15/shell-ux-changes-the-research/ https://blogs.gnome.org/shell-dev/2021/02/15/shell-ux-change... for an example. They don't so much test with end users as gather anecdotes (and then largely ignore test results that contradict their existing design guidelines anyway).