I may be missing something (I don't understand tax stuff well), but if they write off $X losses, and pay $X less taxes... doesn't that mean the American people are paying the same either way in the end?
Thus the government is getting it below their cost. Not by the full $X, but by .79X.
It's never that simple with taxes, of course, but that's the gist of if it. A writeoff isn't the same as free.