Everything old is new again on network television, and without apology. As the TV industry rushes into the future with streaming services, traditional broadcasters unveiled 2021-22 schedules that rely heavily on familiar series brands and reboots of decades-old shows. Among them is CBS’ “CSI: Vegas,” a new version of the hit drama that debuted two decades ago. The networks’ plans also reflected notable efforts at promoting diversity and social activism. Fox will air “Our Kind of People,” a series about upper-middle-class Black professionals who vacation on Martha’s Vineyard. ABC is remaking its old series, “The Wonder Years,” but this time with a Black cast.