From No Quarter:
[...]At the end of the primary season, the Republicans have 29,485,776 (which is an increase of 9.2 million votes over what they turned out in 2008). The Democrats, by contrast, fell from 36,919,660 votes in 2008 to only 28,317,654 in 2016. How do you lose 8.5 million votes and declare victory?
Hillary generated zero enthusiasm. Hell, in 2008 she snagged 2,608,184 votes in the California primary. This year her support plunged to only 1,841,285. That is a loss of almost 800,000 votes.
Whatever problems may exist with Donald Trump, they pale when compared to the troubled candidacy of a screeching bitch that people do not like. It is that simple.