I'm not an economist by a long shot, but I would like to propose an alternative model: Whenever a bank gives out a loan, it not just creates the money that is given to the debtor. It also creates the money that will have to be paid as interest, and gives that money to the government. That could be the government's primary income stream, instead of taxes. And it guarantees that there is always enough money in the system to pay all outstanding debts.

(Looking forward to more knowledgable people pointing out the inherent flaws in this idea.)