He's had tons of exposure and his message has received widespread attention.
Not really. He's gotten only 1/5th the media coverage of Trump. The media has been really ignoring him in the hope he'll go away.
Bernie's a guy that enough Democrats believe can't win, and they don't want to hand over the WH to the GOP. That's Bernie's problem. It's also probably the reality of the situation.
In NH, he beats Trump by 9, while Mrs. inevitable only beats Trump by 2.
Once the "socialist" issue becomes more prominent, that will change, at least nationally.