Why? They get paid $10 every time spam is reported regardless of the outcome. Trained staff listening at 3x speed with AI assistance could classify 3 obvious spam calls in a minute. If you can't turn $1800/hr per employee into a profit center I don't know what to tell you. That's a lot of money to cover for extreme outliers.

Eventually the obvious spam callers would all quit and the volume would reduce to a handful of borderline cases. So the spam department wouldn't make a lot of money anymore, but the volume would be so low it would barely register.