The longest-running original series on Netflix is coming to an end. Jane Fonda and Lily Tomlin have played “Grace and Frankie” for seven seasons, telling raunchy and honest stories of older women. After co-creating “Friends,” Marta Kauffman thought up the Netflix hit “Grace and Frankie,” which made it to an unheard-of 94 episodes. While Netflix has been offering a high volume of shows, only to drop many scripted series after a couple of seasons,  Kauffman is not surprised that the big-volume approach has led to problems. “We’re going to do a little bit of everything in the hopes they’ll be a niche audience for every show,” Kauffman says. “And there isn’t a niche audience for every single show.”