Which is better: for the government to inject really huge amounts of real money to fill in for all the imaginary money that had been created out of thin air, or to refuse and let the holders of imaginary money get whatever pennies on the dollar back up their assets?
If there are any holders of imaginary money whom the government really does need to protect against loss, the government should pay those particular people directly rather than trying to prop up the House of CarDS.
No matter what the government does, the House of CarDS is going to come down. The only way to prevent it would be for the government to slash the value of a dollar by more than half (propping up the House of CarDS with more money than presently exists worldwide). Given that, I see no reason to spend real money to preserve the illusion of imaginary money.
I wonder how many pension funds and insurance companies had money in that House of CarDS. A sobering thought.