This only works if you consider the panel a commodity that is interchangeable. TVs are so so different from model to model.
The quality of the picture is much lower than high end budget tvs like the Hisense 55U6G. If youre buying a TV primary for the panel, to watch video, being "dumb" isnt going to take preference for me over the better panel.
[0] indicates they earn some 10-20$/year for vizio and 40$/month ([sic], article probably meant year) for Roku from advertising. With a lifetime of a TV at about 5 years this puts you in 100-200$ extra territory.
TFA provides the evidence that they profit more from this that from what they get from the hardware itself. So more than $400 over the tv's lifetime these days ?