You're missing a piece of the puzzle actually - this goes back to George Walker Bush's presidency.
Democrats were being extremely obstructionist in GWB's federal judges. Republicans were considering throwing out the filibuster in response. Moderates from both parties got together and convinced their respective sides to back down and let judges get through while maintaining the filibuster.
In 2013, the tactic was pulled out by Republicans, and the Democrats used the - given the history of this tactic - unsurprising response after some time. Which, of course, led to 2017.
Democrats were being extremely obstructionist in GWB's federal judges. Republicans were considering throwing out the filibuster in response. Moderates from both parties got together and convinced their respective sides to back down and let judges get through while maintaining the filibuster.
In 2013, the tactic was pulled out by Republicans, and the Democrats used the - given the history of this tactic - unsurprising response after some time. Which, of course, led to 2017.