How many senior developers do you need to maintain an existing e-commerce site? Not that much. The can hire entry-level / students to do the content. They can re-use the print designers to make the banners. They can automatize catalog management or dumb it down enough so that a manager can do it.

I've spent a lot of time developing e-commerce website for (smaller) companies and none of them required 200+ seniors. Most were small highly skilled teams of individuals with large skill sets.