Trump got elected because the two Presidential candidates in 2016 were the two most disliked in recorded US history :

https://fivethirtyeight.com/features/americans-distaste-for-both-trump-and-clinton-is-record-breaking/

Trump also lost the popular vote by the greatest margin of any President in recorded US history (2.86 million ballots.)

In essence, he won the US Presidency in 2016 because :

"The electoral college is a disaster for a democracy."
- Donald J. Trump
   1:45 AM - Nov 7, 2012