Yup. They shouldn't exist. It's an outrage that they do. They don't pay the reviewers. They charge the authors (who pay the ransom typically from taxpayer fund

Yup. They shouldn't exist. It's an outrage that they do. They don't pay the reviewers. They charge the authors (who pay the ransom typically from taxpayer funded research grants), and they charge the readers, who are either the public or said academics again. But the reason they do exist is that they have the monopoly on issuing the only acceptable currency that dictates the life and career of academics: publishing their work in "high impact" publications.