The entire point of TV sets is to show beautiful moving imagery, yet the application software that runs on them is almost always lame and terrible. The vendors probably can’t police every random streaming app they support, but they fully control the top level software, so it should be a flawless 4K experience with every image authored in HDR and perfectly pixel centered, all smoothly animating at 120 fps. The GPUs tend to be underpowered, so it would take care and effort to make it happen, but it absolutely could.