the vast majority of D’s do NOT want Hillary foisted off on them
they are attracted to Bernie because he is more honest and has a far less rotten record in political office
the Bernie surge will only end if and when a more acceptable (to the majority of D’s, that is) main-stream Democrat of any prominence seriously starts to campaign for the D nomination
until that happens, we expect Bernie to keep doing quite well (despite the Soros opposition and funding of disruptive street thug gangs to mess up his speeches)
the vast majority of D’s do NOT want Hillary foisted off on them
Dems are sheep who will follow whatever figurehead they are given by the party. Sanders, Clinton, Biden, etc. Matters little who the nominee is.
30-40% maybe. Not the vast majority.
Add up those who actually want Hillary, those who go with the frontrunner, and those who don't want to make waves, and there's your majority of Democrats.
Maybe this is one way the system is rigged: outsiders have to enter early to get money and name recognition, but if they enter early their campaigns peak early, and by the time the primaries actually happen the front-running insider with all the money can steamroll over the challenger.