Why did Moses not pray for Korach’s assembly to be saved from death as he did after the sin of the Golden Calf and the spies?

This source-based Torah study examines the question: Why did Moses not pray for Korach’s assembly to be saved from death as he did after the sin of the Golden Calf and the spies? The canonical Hebrew discussion develops the issue through the weekly Torah portion and the sources cited there, preserving the distinctions, tensions, and practical implications of the original text. This localized discovery layer does not add any new halakhic, medical, legal, scientific, historical, theological, or empirical ruling or claim beyond the canonical Hebrew source.