Geez. How many times we got to plow this ground on these forums?
Superman, Wonder Woman, and especially Batman ain't goin' away. DC might tinker and tease, but Clark Kent, Princess Diana, and Bruce Wayne are here until DC turns out the lights, no matter how much one segment of long-term fans would like a new chapter.
Because Bruce Wayne is here to stay, that means Arthur Curry, Oliver Queen, et al. are too. That also means that Dick, Garth, Donna et al. are limited in age, ability and importance.
Progression and suçcession are what Earth 2 was for. It won't work in a ongoing main continuity. I wanted it to back in 1986, but it doesn't.
You let the clock tick, it'll overtake Dick and Donna, and eventually, Damian and Cassie. None of whom have the narrative power of their source characters.