I imagine that the Clintons are pulling every string, cashing in every favor, and making every credible threat they can behind the scenes to keep anyone else out of the DNC field.
What remains to be seen is if they'll run out of strings, favors, and threats before or after the "Hillary inevitability" is established, and they figure the whole DNC and the MSM HAS to pull in behind her, whether they like it or not.
I also have to wonder if Bill secretly wants her to fail... just because... he's Bill. And perhaps even despite all the stuff he's done to deserve it, there's that whole issue of how it's so hard to "Kiss the lips that have been chewing your ass all day..." etc. Now imagine that for a couple of decades. Political-sham marriage or not.
And if anyone that has Bill's confidence, but not Hillary, and the power to do anything about it and knows this.