It ended with Amir Johnson.
With the 56th pick in 2005, the Detroit Pistons selected a 6'9" power forward who reneged on his pledge to attend the University of Louisville in favor of declaring for the NBA Draft. In 13 seasons since, Johnson has put together a solid career in the world's best basketball league, contributing to playoff runs with the Pistons, Toronto Raptors, Boston Celtics, and the Philadelphia 76ers, where he still claims a spot on the bench.
But Johnson's selection would signal a change that reverberates across the NBA and college basketball to this day, as no other American high schooler has jumped directly from the prep level to the pros thanks the league's collective bargaining agreement which required minimum age of 19 and that draft entrants be at least one year removed from high school.