Turns on, has sound, and backlight appears to turn on, but no picture.

When I plug my PS4 into the HDMI I can hear the audio but still no sound. My PS4 can also plug into my computer monitor HDMI port and works as expected, so it doesn’t seem to be a problem with the device or HDMI cord. I don’t have cable, but if I go to the cable/TV setting I can hear static as expected, but again no picture. I also can adjust the volume with my remote and can hear when I increase or decrease volume as expected, but the volume bar doesn’t appear on the screen. So it looks like everything I can think of works perfectly (sound, changing channels/inputs, adjusting volume, etc.) except for the total lack of picture. I don’t think the picture is just really dim either; I tried the trick where you turn out the lights, turn on the TV, and then shine a flashlight on the side, but still nothing shows up. If it’s the main board, I can probably buy a replacement on ebay for $30-40, and it seems simple enough to just plug it in to replace the old one.

What would cause the panel/LCD driver board to fail?

The LCD driver board is what controls the matrix of rows and columns of your LCD screen It uses Gate drivers (multiple IC's for that task) Those can fail just like any other device. It is not common to totally fail but common to have a segment on the LCD fail. That is why I think it is unlikely bu talways possible. I want to make sure that you understand that we can only diagnose based on your description and some of our experiences and we can be wrong. No misleading or malice involved when it happens :-)