Comment by woodruffw
(Author of the post.)
The underlying premise here is that supply chain security vendors are honest in their claims about proactively scanning (and effectively detecting + reporting) malicious and compromised packages. In other words, it's not about eyeballs (I don't think people who automatically apply Dependabot bumps are categorically reading the code anyways), but about rigorous scanning and reporting.
Maybe it's more about mileage (attacks that actually happen) than eyeballs.