It was announced Wednesday that the 2021-22 season would be Mike Krzyzewski's 42nd and last as Duke's head men's basketball coach. Those born after 1980 don't know a world in which Coach K is not on the sidelines of Duke's Cameron Indoor Stadium. After next season, they will know that world for the first time, and the news that Coach K will step down in a year leaves those of us that know him with an odd, bittersweet feeling. It is the end of the longest run of sustained excellence in college basketball history, maybe in the history of sports.