Is it reasonable to expect concrete examples of ephemeral decision making that happens within opaque organizations, given that the overwhelming majority are not held to explicit disclosure of their decision, let alone a verified paper trail held to such a rigorous standard to count for reasonable proof?

The best you can hope for from a potential employer is to be told they hired someone else. The default experience in America seems to be that they'll simply ghost you.

Many examples were given, please read the linked article. And again, in a society where everything is monetized, you can argue that creditworthiness is a just proxy for anything. So if basic water and electric access or housing access can be, so can anything else where you pay money for a service. You could argue dating apps should have access to credit scores and I wouldn't be surprised if some tried.

> Which institutions?

Credit bureaus...