the right answer is because they already did in March of 2008 and you think they will do it again
I do think Treasury's past actions provide a clue as to what they could, and probably will, do in the future. That includes their preferred-to-common conversion with AIG and nearly doing that with FnF in late 2020.
I see far too many calls for Treasury to just write off the seniors because "they have been paid back" or various moral/ethical reasons. It should be clear by now that Treasury cares absolutely nothing about what any of us think they should do. They have shown a willingness to screw over shareholders many times in the past, and the primary way in which they can do so with FnF only hurts the commons.
You really are saying they did it once and they will do it again.
Yes. I think the evidence supports my thesis far more than its inverse.