Among the first things Greg ever wrote about the Kingdom of Sartar was the following:
"<Sartar's> magic turned smart men into chieftains, good men into loyal followers, and enemies into pack beasts. It is said that he took over the valley without a fight, though that is an exaggeration since others did his fighting for him. But the transition was an easy one and he soon organized the robbers into a principality. After marrying the Feathered Horse Queen, he was named King and Dragon Pass rapidly grew in power and prestige.
Under Sartar's rule, the tribes turned from pillage to trade. Sartar and the Queen set up tax posts, guides, and treasuries. Sartar also built roads and forts to protect the traders from possible nomad raids. He fostered literacy, experimentation, and luxuriousness upon his subjects. His short-lived dynasty grew and soon would have rivalled any empire for sheer splendor had it survived."
When I was working with Greg on the Guide to Glorantha, we decided to go back to WBRM as a touchstone. RQG very much reflects the Glorantha of WBRM, the Redline Histories, Pavis, Cults of Terror, and King of Sartar. But it does require rethinking some of the assumptions from the HW period. First and foremost - the nature of the Kingdom of Sartar itself.
Under the reign of the House of Sartar, Boldhome and the other cities were wealthy from trade. The Prince had substantial revenues at his disposal. Masons could build impressive stone buildings, grand temples to the Lightbringers could be founded - including markets, libraries, and hospitals, paved roads could facilitate trade, mercenaries could fight for the Prince, and so on. Caravans carrying goods and luxuries from all over the world traveled through WIlmskirk, Boldhome, and Jonstown, paying a toll for Sartar's protection (and for the convenience of the roads, inns, etc.).
Tribal kings, chiefs, priestesses, etc. all looked to the Prince for gifts and support. Cities bought large amounts grain and meat, and their citizens had the right to an allotment of the public stores. It should be reminded that New Pavis is stereotypically Sartarite in its layout, its political institutions (mayor, public granaries and warehouses, etc.). It is unusual in the presence of the Big Rubble, the nomads, and so many adventurers seeking treasure in the Rubble. It is not unusual in its institutions.
There's no question about it, under the rule of the House of Sartar, Sartar was rich. Probably richer than Tarsh (dispute its smaller population), definitely richer than most Lunar satrapies. This also helps to explain the Lunar Empire desire to conquer Sartar - instead of it being an unimportant backwaters, Sartar was a rich, strategically important kingdom that controlled the bulk of all trade between the Lunar Empire and the rest of the world (let's skip the Red-Haired Tribe and the Ralios caravans and whatever trade goes through the Janube Valley).
It wasn't the Kingdom of Tarsh that defeated Tarkalor and the Feathered Horse Queen at Grizzly Peak - it was the Heartland Army and the Red Emperor (the Lunar advance was stopped at the Battle of Dwarf Ford).
Trade continued during Lunar Occupation, although not at the levels seen during the rule of Sartar’s dynasty. The Etyries cult played a greater role in trade, although the Issaries caravans continued to travel between the Holy Country, the Lunar Empire, and Prax under the protection of the Lunar military. However, Lunar tax collectors and military leaders prospered more than the cities, as they took much of what used to go to city and tribal leaders. So during the Lunar Occupation, much of the traditional Sartarite elite became poorer, the cities stopped buying as much grain and meat from the farmers, and it all trickled down.
With Sartar’s liberation, the Lunar Empire is no longer able to tax trade through Dragon Pass but also there is no longer Lunar protection of caravans. With political disintegration, much of Dragon Pass has returned to the state of banditry that prevailed prior to Sartar’ arrival. That's the situation at the start of RQG.
This might explain some of my desire to linguistically clear the decks of "misleading" terminology like "cottar, carl, and thane" or of using Early Medieval Ireland as a model for understanding Sartar. Heck, if anything Classical Macedon or the Ghaznavids might be a better analogy (although those have lots of limitations as well). At the very least, it helps me see Sartar for the very unique place it is.
Anyways, good food for thought I hope!