Unless Clinton dies or eats a baby on national television Sanders has no chance. His purpose is to bring the issues that liberals care about to the forefront but the truth is ideological candidates, whether hardcore liberal or hardcore conservative rarely win. The last time the Dems nominated one was George McGovern and well...just take a look at that electoral map.

The Democratic Party doesn't want a repeat of 1972 hence why all their eggs are in Hillary's basket. Biden not running was a clear signal that the entire establishment is behind Clinton and they prefer her to be the standard bearer.
And what the establishment wants the establishment always gets.