Well, there's also other issues. Some people might believe Bernie can achieve massive change but they don't want that. So in that case, again, it doesn't hurt Hillary.
Some Dems might prefer being closer to the status quo.
The fact is, though, that Bernie is supposed to be the candidate of "needed change." The fact that he's not even winning that is weird. Even I agree Bernie is more likely to bring "needed change," instead of "realistic change." How is he losing on this question?
Again, my guess is a lot of the voters, minorities, see "needed change" related to things more like immigration and LGBT discrimination, etc, and Bernie isn't seen representing that.
This is a knock on Bernie's message. He can't show himself to be "change" to minorities.