Michigan going for biden pretty much slams the door on sanders. Its sad but most of his historically flaky target audience once again just didn't show up to the booth. Plus, he's not up against a widely disliked figure like hillary so he's also lost a chunk of the 'not-hillary' vote
Looking at the turn-out figures, biden atually looks decent in the key swing states so far. Not an inspiring candidate by any stretch and the country basically spins its wheels under him, but the medias fear-mongering over who can beat trump is probably be enough to prop him up in the general