Flash has had a long-running live action series and still has only one ongoing book. Plus the occasional mini. The Flash is one of DC's top characters and is an example of a major property that gets very little push in comics.
Johns was the one who was supposed to write it. If he had it would have never published on time. See also Shazam. Just give a JSA book to someone else. You have the Stargirl show. Sheesh.