For years, the NBA was dominated by the big man. Size was everything if you were building a team, and your star player wasn't a big man, you were doing something wrong. Going back to 1984, the year Michael Jordan was drafted, no one believed that he could be the savior for the Chicago Bulls because he was a 6'6" guard and not some 7'0" giant. MJ flipped that narrative and slowly started trend of guards and forwards being able to be stars too.
This trend continued to progress into what we know today as positionless basketball. Many different fads had happened, like the small ball era, where every team was trying to have maximum spacing by not playing a center.