the prison-industrial complex affects the number of people in prison in the US

Surely its effect is above zero, but I'm highly suspicious of how significant it really is. I wasn't around back then, but from what I know, it seems pretty evident that the crime wave of the sixties, seventies, and eighties produced a genuine popular sentiment in favor of tougher criminal law, which hasn't subsided to this day. In fact, this is one of the few major political trends in recent decades that looks like an authentic democratic response to popular demand.