SE Linux is enabled by default in Debian, Ubuntu, Fedora and Manjaro (iirc), so I stopped reading at the introduction. The exploit presupposes the lack of this basic hardening.
Fedora Silverblue/CoreOS look like a massive step in the right direction which no other mainstream distros are working on.
Fedora also seems to be the only distro willing to set sane defaults for everything (SELinux, Wayland, CGroupsV2, soon to be pipewire, python 3) while every other distro waits around for someone else to make the first move.
How recently? Ubuntu 20.04 dropped python 2 completely.
except for fedora they don't support selinux well