2012 is underdiscussed as, arguably, the most consequential election of the 21s century in America. It changed a lot of states' voting history. The American political map would look a lot different if Mitt Romney had become president. Romney losing was the "final straw" for many Republican voters that led to Trump...
Republicans have a very hard time being patient and waiting for their parties turn to take over the White House; had they just waited for 2016 and gone with a Kasich or Rubio, the map probably would have looked quite red. Instead, Republican's (2009-now) are impatient and impulsive, overreact and become more reactionary to each election loss they witness.