Black is beautiful.
For a long time, only the Raiders knew this. They were the only sports team that featured black as a primary uniform color. But eventually other teams, like the Pirates, Penguins and Giants, began to display black more prominently. Then expansion teams like the Rockies, Marlins, Jaguars and Panthers, made black part of their color scheme from the very start.
Soon, established teams like the Reds, Mets, Blue Jays and Royals adopted black for the first time in their history, and there was no going back. Black was here to stay.
So it was with sports cards. 1971 Topps was a breakthrough. 1986 Topps less so, but still very noticeable. But no one dared to use black prominently on the BACK until 1992 Pinnacle.