Concerning scarcity and specialization, You forget there is one resource that is very scarce. Time. On the server I play on, I could go gather my own wood and Iron and such, but I'm only on for a few hours at a time if that, and I have better things to be doing. Therefore, I and many other midlevel players trade for raw resources. It is the same reason that even though the real world is industrialized, we still have laborers. Sure, the CEO of GE could go work in his own factory, or could cook his own meals or drive his own car, but his time and energy is limited therefore he does not. Same reason the CEO of Ford doesn't work in a steel mill.