In most mini LED TVs released today, the backlight can consist of thousands or tens of thousands of LEDs. Yet most of the LEDs are grouped into much less dimming zones, around a few hundred or around a thousand. It is ideal for eventually every LED to become its own independent dimming zone so that you can have a TV with tens of thousand or a hundred thousand dimming zones in order to maximize the contrast of the display and compete with self emissive displays like OLED and MicroLED. It seems like for the past few years or so, the amount of the dimming zones on these TVs has only increased marginally.
From my research, one reason is because of costs- the 1st few iterations of mini LED TVs used a passive matrix PCB substrate and a passive matrix would make it too expensive to enable much more dimming zones. However, BOE which is one of the leading LCD display manufacturers recently started mass production of mini LED LCD displays with an active matrix on glass substrate so it shouldn't be more costly to get to ten thousand dimming zones. Yet we still see their display is only limited to around 2000 dimming zones with 20,000 LEDs.
This leads me to believe that developing the backplane is not the only issue in enabling more dimming zones. I feel like the CPUs currently used in TVs are not fast enough to handle an algorithm that can process much more dimming zones.