Voter turnout was only 54%. Of this number, only 46% of voters chose Trump. He won 62.9 million votes, or about 19% of the total US population. Slightly Less than 1/5 people in this country voted for him. Clinton didn't do much better, but she did win the popular vote by 3 million
1. Both candidates are highly disliked. That's why voter turnout dropped and also why smaller parties got a bit increase in votes.
2. A lot of democrats stayed home because they truly didn't like Clinton. The GOP was better at unifying people to come out and vote for Trump even if they didn't like him, just to give him a chance. Democrats weren't good at this. Many progressive voters didn't vote at all.
2. Trump won where he needed to in States and won the electoral college.
It's really about his message ringing to voters to give him a chance. His voters turned out in large numbers, plus some dems staying home.
Remember, he got lucky winning blue by tiny margins.
Also, his approval dropped a lot since then