This whitepaper explains why traditional email security is failing in the age of AI-generated attacks and introduces a new way to evaluate security platforms. It outlines three generations of email security (rules-based, machine learning, and LLM-native reasoning) and compares them across three critical axes: detection completeness, accuracy, and speed of correction. The paper argues that technique-based detection can’t keep up with novel AI attacks, and that intent-based, reasoning-driven architectures are now essential for effective, scalable defense.