The NBA adopted the 3-point line from the ABA. For decades, it was barely used. Then Curry happened. In 2015-16, the Warriors took 31 threes per game. Now every team shoots 35+. The 3-pointer didn't just change basketball — it IS modern basketball.
Before the shot clock, teams could hold the ball indefinitely. The Pistons beat the Lakers 19-18 in 1950. The 24-second shot clock saved basketball from becoming unwatchable. It's the most important rule in NBA history.
Before 2001, NBA rules required man-to-man defense. Legalizing zone defense changed everything — it made isolation harder, increased ball movement, and eventually led to the pace-and-space era we see today.
Daryl Morey and the Houston Rockets proved that mid-range shots are inefficient. The math says: shoot 3s or layups, nothing in between. The mid-range game nearly died. Then DeRozan and Jokic brought it back. The debate continues.
Kawhi Leonard sat out 22 games in 2018-19 for "load management." Won the championship. Now every star rests regularly. Fans hate it (they paid for tickets). Teams love it (healthy stars in playoffs). The regular season lost meaning.