For the last year, Southern is nothing more than a brand of GTR (Govia Thameslink Railway) who operate the Thameslink, Great Northern, Gatwick Express and Southern brands. So you have this large franchise running trains from King's Lynn to Brighton who are trying to streamline everything from ticket offices to counductors on trains to maintain profits for their shareholders. Fortunately this franchise is only until 2021, when it's very likely the Metro services from PR/ED/ND will be handed over to TfL, leaving the profitable services out of London to the private sector.