The resurrection of the public plan?

Have I seen twenty MSM articles on this theme in the last five days?  Yet the betting odds are only slightly above their minimum point.  Right now the contract is running at about twenty rather than eighteen or so a few days ago. 

I don't follow the ins and outs of the trenches (try Ezra Klein), but as an outsider I don't understand why in strategic terms the Democrats are resurrecting this idea.  It's their most likely path to failure, namely that they can't pass a public plan and can't easily go back to a bill without a public plan either.  Any bill that is passed will be revised repeatedly in any case, so there's plenty of time to try to get a public plan in the future anyway.