A bipartisan moderate that everyone loved, recommended by both parties, poised to take the nomination, then blocked for years by the Republican party just as a total partisan f-you to Obama.
He was nominated on the 16th of March 2016; the election was on the eighth of November of the same year, and his nomination expired on the third of January 2017, less than a year later. No matter how you slice that, his nomination to the Supreme Court wasn't 'blocked for years.'
Garland would have made an excellent choice instead of Kagan, or even Sotomayor, if there was a desire for a more balanced, more centrist SCOTUS. However after those two nominations replacing Scalia with Garland was obviously a bridge too far which the R's could not accept. As unpopular as it may have been, In a way, I don't really blame them, and it seems to have paid off for them in the long run.