from what i've gathered in my many fruitless attempts to make 1080p work, there were more than a few plugins that faked the user agent but that stopped working a while back, i dont even know where to begin to figure out how the netflix plugin works because it has no effect on other streaming services like amazon prime video and hulu, hbo.
i've spent a good few hours just just today trying to get chromium os to run in a vm only to find out i cant even get it to work in a decent resolution without installing vmware tools but how does one do that with chromium os. wont run for me on vbox/gnome-boxes/virtmanager. anyway, point being it allows you to install the proprietary junk in chromium (browser) so 1080p works for everything without plugins but google works very hard to keep full hd playback from working on linux.
i really like your one-liner for netflix btw, great stuff