Does it mean that most 1000-nit hdr tvs use VA panels? Which may also be the reason why Sony doesn't use the Ultra HD Premium certification even on their high end UHD TVs even though Sony is a member of the UHD Alliance.
No. IPS panels offer enough transmissivity to reach 1000 nits with the right light source. It's just that they can't block the light well enough to offer good blacks. Increasing the light source intensity emphasizes this even more (and local dimming will often cause cloudy splotches).
Sony's high end TVs use VA panels (X930D, X940D and Z-series) and offer good contrast. I don't think they can compete with LG's OLED or Samsung's VA TVs if they stick with IPS for their entire lineup.
I think Sony purposely omitted UHD Premium labeling, because it'd make most of their TVs look bad (only the X930D, X940D and Z-series lines meet the UHD Premium spec).
A TV can meet the UHD Premium spec even with just a 540 nit maximum intensity, as long as the blacks are deep enough. A lot of Sony and LG TVs exceed this intensity limit, but only the high end VA Sony models and OLED LG models offer blacks deep enough to meet the spec.
Unless you have a pure black image to play with, most people will not notice these black levels.
Normal movies rarely have all black sequences except for the End Credits which most people skip.
Unless you crush the intensity extremes, you'd still notice less contrast on lower contrast scenes. You get a "flatter-looking" image without such an enhancement. Most TVs with lower contrast panels tend to do this to hide the shortcoming (which becomes very evident during calibration).
