You are assuming that the credit card companies pass along the money quickly. They don't, in some cases holding on to it 'for the protection of thier customers' until after travel.
Of course it depends on the credit relationship between the airline and the cc company, but if an airline looks shaky there are holdbacks. These are propriatory agreements which terms rarely see the light of day.
A few years back a Slovak airline went bust after losing much of their cash flow. Not saying this was the reason they went bust, it wasn't, but it likely expedited the event.