My two cents: The average American has a literacy rate of 7th-8th grade and not only does Trump talk to that level he also repeats things constantly so people can remember it. Couple that with all conservative biased media constantly blasting the same messages people believe Trump was looking out for them. Compare to Hilary who has been painted as out of touch with voters and courting high value donors since Bill was president and the Bernie thing she needed to capture more independents but she didn't.