George Lucas always said they would run for 5 seasons, regardless of ratings.
But to be honest I think Disney plan to Market Star wars with their other franchises as epic teen/adult Cinematic experiences (Which it once was), and are making a conscious effort to move away from the pre-teen Saturday morning cartoon, that has dominated Star Wars for the last decade, and put all efforts in to centralizing our attention on Episode VII. When I was a Kid, Star Wars was massively popular as it is now, but It was cool, and respected by other film makers and fans of other genres. Now its kind of a Joke outside of kids, and dads who want to indoctrinate their kids lol. Star Wars can be epic once more!
also, Detours, and other comedy/kid stuff has also been put on the back burner