I can see that backfiring.
All of a sudden interest rates are 10%. Then, all of a sudden all of those people who have maxed out cards suddenly find their cards now have a higher credit limit. They go out and charge that card up to the limit. Interest reduction ends, cards suddenly have 29.97% interest on double the balance and the max balance is now where it used to be, or their card gets cancelled and they have to continue paying without any recourse to a new interest reduction if one should occur because they are a bad credit risk and have jumbo utilization.
You'rec right. There'd have to be a rider that it applies to get you out of debt and your upper limit is frozen.
Those people deserve to go bankrupt.