As the video points out, a lot of the work in xorg (and Linux in general, fwiw) is done by red hat engineers. So red hat cutting on that investment bears direct consequences for everyone else. Unless of course someone steps up and takes their place in maintenance, but it’s not gonna happen, which is literally why Wayland (and not some revamped xorg) is the future of Linux desktop.
Also, red hat’s decisions often trickle down on most other distros. E.g.: systemd, pulseaudio, pipewire, gnome, not including proprietary codecs, etc.
So, they technically don’t arbiter, but they definitely set the pace.