[ding_dong_daddy_from_dumas]

but far less has actually flowed out of the Treasury, most of it never will (since most of that number consists of guarantees of things that aren’t going to fail)

That's your opinion, but remember Bush and McCain saying "The economy is fundamentally sound" before telling us that it was all going to fall apart unless we coughed up $7B.

[Arguendo]

Well I guess if every major bank in the country catastrophically fails and every company goes bankrupt and defaults on its commercial paper...

And even so, it looks like that $8.7 trillion number includes monetary stimulus, which is completely different from expenditure of taxpayer dollars. They obviously wanted a headline-grabbing number, not a serious estimate of the cost of the bailouts.