The election of Trump in 2016 was the culmination of many factors from the previous 50 years, all of which lead to a very predictable outcome.

• Reaganomics loosening regulation on corporations, lowering taxes on the wealthy, and defunding public education
• Rush Limbaugh and Fox news fostering rural nationalism
• the advent of the internet which allowed those people to find each other and exchange their poorly informed ideas
• the perception that politicians were prioritizing "them" over "real Americans"
• 9/11 and the resulting surveillance state and 24h sensationalist news cycle.

By the time Obama was in office, Republicans and Democrats lived in different realities. Republicans just wanted someone who was willing to stand on stage and spout their version of reality, and Trump is the right combination of insecure and stupid to want to do that. He was an inevitable symptom of a decades long problem.