TVs are cheaper per unit area than insulation windows, could be providing a view of exactly what a windows would with streaming cameras, but could also let you travel the world by providing votes from other locations. They would also let you up the r value of the walls easily :)
It is potentially an issue for long-term eye health. If your eyes spend most of their time within a small range of focal distances, the muscles you use for focusing essentially fall out of shape. This can cause a person to need multi-focal glasses sooner than otherwise.
It also limits the mental health benefits of looking “out a window.” Your brains knows whether a scene is real or fake based on focal depth, regardless of resolution.
There is no need for a TV to REPLACE the window
Even bird cages have openings. Trapping a student in a hole is rather miserable.
However in fifty years we might not want to open the windows anyway.