It seems you missed the part where you posted while I was posting my reply. Read my edit.

Also, the fact that it was too much work to make full scale conventional towns does not detract from my argument that lack of NPCs make sense (in game). Actually, it fits perfectly well together.

They're not making fully flushed out towns because it will take too much work (for a game they have been working on for years already), but if they are not gonna have fully flushed out towns, at least let's make it make sense in the game too, which they do.