The year that the nba went from short shorts to baggy shorts?

I have also wondered why the NBA changed all of a sudden. The NBA wore short shorts from the time of George Mikan in 1946-1947 to the time of Dominique and Larry bird in 1988. Why all of a sudden, after something had been done for so long, something can change, beats me. My guess is 1990, as that is the year everything changed.