Other telcos have also been in the dog house with TPG Telecom Ltd ( ASX: TPM ), Vocus Group Ltd (ASX: VOC) and Amaysim Australia Ltd (ASX: AYS) nursing big losses as well. Coming back to Telstra, Morgan Stanley thinks our largest telco is likely to follow in the footsteps of French mobile operator Orange France in wondering the mobile wilderness for several years. Mobile is Telstra's biggest earner and arguably its most important business. The impending entry of TPG Telecom as the fourth mobile player in the Australian market shares a lot of similarities with what happened in France when Iliad SA became that county's fourth player. Morgan Stanley noted that incumbent Orange France has only just posted its first positive quarter for mobile revenue in the three months to end December 2017 after six-and-a-half years! "Why?