No. Their money was worthless because it wasn't accepted anywhere else on the planet. Monopoly money had greater value than the Ruble.
Since it's dumb to save while you still have credit card bills,
Your assumption is false.
lets assume that everyone has first paid off the plastic and tears it up. What "greater business activity" would there be with everybody's money in the bank gathering dust, rather than coursing around the economy transporting economic energy?
You are assuming a 100% savings rate beyond basic necessities. That is impossible and no one has or would suggest such a thing.
You have also forgetton the part that if everyone was responsible in saving for retirement so they would be confortable there wouldnt be a need for SS, Medicare, and a whole host of other government programs and the budget could be slashed in half or more. Peoples take home pay would explode and their economic activity in the market (consumer, not capital) would also rise while their savings and investing would rise as well.
The biggest obstacle to saving and investing today is that for most people greater than 50% of their income is paid in taxes.
Shout it from the housetops, brother!!!
Assuming that credit card rates are higher than your return on investments, paying off your credit cards is the smartest investment you can make.
Tax credits for retirement accounts might make a bit of a difference, but not enough to matter.
If a keeping a credit card balance while investing your spare cash were a good idea, then the thing to do would be to buy up to your limit with a credit card and put the spare cash in investments. [/bad idea