In the framework proposed in the article, if an insurer's clients don't stay out of trouble, the insurer has to pay fines on their behalf. If they can't pay their insurance premiums, they become indentured servants until they can.

The indentured servants aren't free and probably aren't profitable. These are people who can't make enough money on the open market to pay their premiums, so it seems unlikely that the workhouse will be able to generate more profit per worker than that. Given that insurance companies will lose money for everyone that converts from paying premiums into a workhouse laborer, they'll be highly motivated to get them back into the real world with a job, modulo the risk of them getting into trouble and causing another fine. So I don't see the incentive you mention to get them to break the contract.