It's true that a lot of established ML techniques were first popularized to fight spam (ie bayesian filtering), but it might also be the case that they're not applying the full might of eg Gemini-3-Pro to every email received. I suspect Gemini-3-Pro would do an effectively perfect job of determining if something is phishing, with negligible values in the false quadrants of the confusion matrix, but it's probably too expensive to use in that way. Which is why things like this can still slip through.