Cohn, Enten, and Silver went from being outsiders to insiders during the Obama era, their politics are basically Obama politics. Bernie's substance on economics didn't appeal to people like that. Remember, some Obama advisers even came out and said Bernie's single payer plan didn't add up and assumed a high rate of economic growth that was unrealistic. The WaPo and NYT were very hostile to Hillary, they even signed an exclusive
deal with the author of "Clinton Cash" to smear her, while they just ignored Bernie or didn't take him seriously. But it's true, in retrospect, his chances of winning were always low.