I disagree with you premise. People are spending time in jail for not showing up to court, not because of their debts. And even jail time is pretty rare for a bench warrant.

Of the situations you listed, the only valid reason for not showing up to court is because you weren't aware. But because the stakes are so high, judges in California require that parties have been personally served by a registered process server before they'll issue a bench warrant for not showing up to a debtor's examination. I assume other states are similar. Correct me if I'm wrong.

I actually think that the process that the courts have for enforcing judgements is much fairer than the tactics that debt collectors often resort to. There's a reason that laws like the Fair Debt Collection Practices Act exist.