Matt Yglesias has a piece in Vox explaining the politics of cramdown in which it tells readers that there was no way the Obama administration could have gotten cramdown through Congress. While Yglesias correctly points out that the Obama administration never really tried, he misrepresented the nature of the problem.
One of the great things about cramdown was that the proposal could have been sliced and diced in almost an infinite number of ways. While Yglesias is undoubtedly correct in saying that a wholesale revision to the bankruptcy code, that would have allowed all mortgages to be rewritten in bankruptcy, never would have gotten through Congress, that doesn't mean Obama could not have gotten a more limited version passed.
For example, the dates at which mortgages were issued could have been narrowly restricted (e.g. 2004-2008). The size of the mortgages could have also been restricted. Does Yglesias know that Evan Bayh never would have agreed to cramdown for mortgages of less than $300,000 issued in a narrow time window, coupled with some huge government contract for a firm he could subsequently work for as a lobbyist in his post-Senate career?
That is the way presidents get bills passed that they actually want passed. (Look at what Obama will do to get fast-track authority when he wants to get the Trans-Pacific Partnership approved by Congress.) Anyhow, cramdown was almost certainly passable in some form if President Obama wanted to go that route. He didn't, end of story.