So, one might ask, why are you spending so much time figuring out royal economics and demographic distribution in developing a game that is so heavily about mythology and magic?
Easy! The spiritual realm is tied to the material world. There is no secular versus religious here. Rather in Glorantha we are all beings that have our feet in the mundane world, and our heads and hearts in the realm of the gods and spirits. Most of our adventures take place in the mundane world, of swords and armor points, where a single lucky hit to the head can be the end of the mightiest. But we call upon the realm of gods and spirits to cast our magic, to change the parameters of the mundane world.
Same thing with the earthly realms of Glorantha. Someone like Harrek might be half-god, but his followers need to be fed and supplied. Argrath might call on draconic magic, but he still needs to finance an army. Even mighty Moonson has limits grounded in the mundane world of matter.
To me this a big part of why Glorantha works as a setting. It combines the fantastic with the material. And it is also why I prefer RQG the best of all the rules systems yet designed for Glorantha as it lets us explore its mythology, while still keeping our feet in the mundane world.