I love this description of developers that Horace Dediu wrote, in reply to comments about WWDC 2014:
Developers don’t just build. Using an analogy of building or construction, they are architects and designers as well as contractors and craftsmen and artists as well as builders. And not of just of houses but of cities and communities. They see and think through tools and techniques for building and innovations in building materials. Innovations which allow them to imagine first and, later, to build new cities in ways that were never before possible.