The purpose of later shortening the line to 22 feet was to increase the number of 3-point shots taken and made. In that respect it has worked. NBA players used to shoot between 25 and 30 percent from that range at the old distance. Now they are over 35 percent and attempting more than ever. The trouble is twofold.
Defenses now know almost exactly what to expect.
Secondly, the area of the court that needs to be defended has been shrunk. The area bounded by the old 3-point line was 875 square feet. The new area bounded by the 22-foot line is 760 square feet.