The basketball uniform has traditionally been a set of singlet and shorts. Prior to the 1990's shorts tended to be very short, but since then they have become very long.
They did not always wear a tshirt and shorts. In the late 70s and 80s they had really short shorts. It was not until the 90s where they brang in the long shorts.
Often the basketball uniform has reflected the style of the times. One example is in the basketball player's shorts. Twenty years ago, short shorts were popular. Now, long and baggy shorts are in vogue.
Originally, basketball was played in long sleeved shirts and pants. By the 1920s, the uniform switched to sleeveless shrits and shorts, which it still uses to this day.