Ask HN: Why aren't there startups to disrupt high interest credit cards?

Isn't that what Lending Club is?

A long time ago there was a market for "signature loans" which were based on a banker's appraisal of your creditworthiness.

Those have been squeezed out by home equity loans (very secure but only available to homeowners who have equity) and credit cards (high interest but easy to get.)

I don't think there's any inefficiencies to be taken advantage of. High Risk means you don't get your money back half the time and so the High APR is needed just to break even on the defaults.

perhaps, some algorithm can better assess risk more accurately and charge a different rate based on the consumer and his or her record. But, my guess is, that's illegal.

Affirm?

Interest rates aren't high for fun. They're high because credit card borrowing is unsecured and high risk. People default on credit card debt all the time, and they also pay it off slowly.