The one handed set shot (taken by stepping forward with the shooting side foot (same foot as the hand you are going to shot with) executed by not leaving the floor has been become extinct at all levels of basketball.
The one hand set shot is really nothing more then a foul shot with a step.
It was the most effective perimeter shot prior to the 3 point line coming into the game over 30 plus years ago at the high school and college levels and the pro levels before that.
The last player that used the one hand set shot at any level successfully was Magic Johnson when he played for the LA Lakers.
The reason that the one hand set shot has become extinct was when the 3 point line was put in at the college level in 1984 and in the high school level in 1987 and the ABA and NBA prior to then.
The reason for that was because the shooters were concerned about when they stepped forward that they might come in contact with the 3 point line, thus nullifying the 3 to become a 2.
In order to be a legal 3 point attempt both of the shooters feet have to be behind the 3 point line when the 3 point shooter leaves the floor, they may land with either one or both feet on the floor inside or on the 3 point line after the shot attempt has left the players hands on the release.
The one hand set shot was one of the best offensive basketball weapons because the shooter did not have to make any commitment to shoot the ball. The shooter stepped forward while bending the knees and if the shot was not there the player could simply pass the ball to a teammate or if live could dribble, or could pump fake and then drive to the hoop,
It was the most difficult shot to defend because the player with the ball had so many options without leaving the floor with the ball. There were few turnovers when the using the one hand set shot.
How many times in today’s game does a player leave the floor and does not take a shot end up committing turnovers, either with a player control foul, a bad pass to a teammate who thinks because the player left the floor like the player is going to shoot the ball the teammate did not expect a pass and turned away to get in position to offensive rebound and the ball goes sailing out-of-bounds.
Or the players who leave their feet does not have a good shot because they are defended well has to get off a forced bad shot before returning to the floor for a travel.
Check out the next game at any level that you watch and see what happens when players leave their feet and do not shoot the ball.
This play causes as many turnovers then any other offensive move a player with the ball can make.
I always had a rule for my players that when you leave your feet to take a shot, then you shoot the ball, but you better have a good shot when you leave the floor with the ball.