Because figures like Cassandra Cain, Birds of Prey, and Stephanie Brown were already granted their own agency and titles at least in Post-Crisis. And the Birds of Prey were primarily made of women too. Birds of Prey were cancelled but knowing how precious that property is to DC it'll relaunch again at some point. There's even talk of Lois Lane getting a book by publisher Jim Lee well at least that's what he hinted at. And Lois got to play a huge role in Superman and Action Comics. She was essential to saving her son from the influence of Manchester Black, she even drove the Batmobile and piloted the Hellbat armour for a spell. Catwoman is getting yet another solo title again. Cassandra Cain is hinted to be headlining an Outsiders title and the writer is a real fan of her. Supergirl is already getting another relaunch. Wonder Woman is even leading the Justice League Dark.