Not that hard to understand. Trump has a very devoted following, but what you see (in the primaries) is what you get. He is a known commodity. Everyone who will vote for him in the primary will vote for him in the general, but there will be very few NEW Trump voters in the general.
DEM turnout has been VERY LOW this year OUR turnout for Trump is EXTREMELY high!!! Do NOT forget the disenchanted Bernie voters they may switch to Trump!!!! I think OUR turnout will SURPASS anything Hillary can pull out!!!