Most people don't get what a phenom Sanders is that he has won office after office and election after election for 32 years without party or much money to speak of.
Normal candidates need a major party and its donors and its media juice. The DNC and the party's most desirable campaigners, including Obama, are all behind Hillary and so is msm.
Guitierrez, for years, a member of the Caucus Bernie founded and still caucuses with, pretended he didn't even know Bernie's name. Guitierrez wants to be the next mayor of Chicago. Think he wants the endorsements of Obama and Rahm, maybe Bubba?
Kamala Harris is trying to go from state AG to the US Senate, something long time Massachusetts politician Martha Coakley couldn't manage without party support, despite a money bomb from Emily's List. Harris endorsed Hillary.
Even though her seat is pretty safe, Warren has been silent and I don't see her endorsing Sanders unless and until he looks like a sure winner. And so on.
My rep's seat is also safe, but he has been on radio saying that, if Sanders is the nominee, the next President will be a Republican. IMO, there is far better chance of that if Hillary is the nominee, but that is beside the point. (It's also a lie or Limbaugh and FOX would be lifting Sanders up, not knocking him down.)
I am not saying it can't happen, but I am saying that we have to be in reality.
Nominee Bernie will have coattails, but candidate for nomination Bernie has an uphill fight. Luckily, he's doing great.