In two words: “Better ROI” “Higher quality” “More scale” Being wide ranging, the skill sets (creative + tech + marketing) needed to do digital marketing, are usually not available in one individual, a team is required. Thus, any user (client) organization wanting to do digital in-house needs to justify to itself why they would staff up with a multiple team. Since digital marketing is not the main business of the user (client) organization, the career path which can be provided within the organization to such people is necessarily restricted.