I remember in 2012 when Romney was drawing big crowds close to the election, and the conservative media was constantly pointing out how Obama just wasn't bringing people like in '08. And then I saw how that worked out.
Bernie Sanders is doing the same thing on the left, but I'm guessing most states aren't going to end up like NH did. Most voters have zero interest in seeing candidates, whether they support them or not. A Trump voter fits the profile that would, kind of like the 1/100 of a radio show audience that has to call in.