It is generally agreed that people often tend to make up their minds based on emotions rather than facts, and hear what they want to hear in order to confirm these emotionally-based opinions. Trump's base has shrunken only slightly, but there are a lot of people who stayed home during the last national election because they didn't like either candidate and are now as energized as a space probe. This time, it will become increasingly difficult for special interest groups to persuade these energized voters either not to vote at all, or to vote against their own best interests.
Hitler also taught that a big lie would be believed easier than a little one if it were repeated often enough, so by and large he restricted his big lies to only these two, with other lies invoked in support of them.
The most important reason that Trump does not pose as much of a danger as Hitler did is obvious. Hitler was a much better speaker! He even made use of lighting, symbols, and audience involvement to drive home his points. Here, with English subtitles, is one of his classic speeches. Judge for yourself.