Viewer independent glasses free stereograpic displays all suffer from the same problem: you need a huge number of pixels (to support viewing from N angles, you need N times as many pixels).
Yep, I was thinking about a lenslet array system with NxN subpixel under each lenslet. The subpixels are view dependent by emitting light directionally using fish eye magnification of the lenslet. For 64x64 subpixel resolution (giving you around 256 view angles), you need a total of 512 megapixels for a 1080p lenslet array.
Well yes, you need to make a new type of display. It’s not a software technique to be applied to existing displays.
The point Isn't that it needs to be new but that the new thing fundamentally is far more demanding. If you have many times more pixels per frame, your GPU has to do more work, your display cable has to have more bandwidth, etc.
Unless most of the scene is static and the camera doesn't move. Then you can do partial update and the cost is proportional to the part of the scene that moves.