Why is there no center in nba today?

"In the 2006-2007 season, apart from Yao Ming, no real center in the league averaged more than 20 points per game. In contrast, the number of strikers and defenders in this statistic is 13. Looking down at the center's scoring list, the second place is Aucour, whose three-point shot is outside the three-point line. Even inferior people like Pachulia and darren potter can be among the top scorers of the center 10 if they average more than 10. The center may have really entered the ice age. The huge body also makes these giant superman face more physical exertion. When Yao became the first center with an average playing time of 34.6 minutes per game, his data didn't even rank in the top 60 of the league. The living space of the center is being completely eroded by the villain. "