Dian Wei dared to say such things because he already had a considerable understanding of Inner Qi Manifestation outside the Central Plains.
The Inner Qi Manifestation practitioners outside the Central Plains typically have little combat experience. Most of their expertise comes from battles before their manifestation, with few cases of genuine combat after reaching this level. In those regions, these practitioners are often the highest-level experts, and life-and-death encounters between them are rare.
As for the Central Plains, any practitioner of Inner Qi Manifestation would likely have faced others at the Ultimate Inner Qi Manifestation level multiple times. Even pinnacle clashes unimaginable elsewhere have occurred here repeatedly. As a result, any remaining practitioners of Inner Qi Manifestation in the Central Plains, unless they've just recently broken through, are at least at Inner Qi Manifestation Perfection.
