I think at this point the Sartarites are easier to explain as their own thing than try to say they are “like so and so”.
For example, with my players who know nothing about Glorantha, I say, “They are an ancient world warrior culture, with feuding tribes and caravan cities. Hospitality and honour are very important to them, and they hate being ruled by outsiders, although they are very loyal to their warlord Prince (who they claim is descended from their divine founder). Their main gods are a Storm God and an Earth Goddess, and have lots of minor deities, most of which share in the myths and stories of their main two gods.”
Some might visualise Kafiristan of the Man Who Would Be King, or they might think of Thrace and Macedon, Vedic India, or even ancient Slavic cultures (I have one campaign where all the players are Polish). But that’s just for visualisation – they know it is actually none of the above.
I mean we don’t say the Melniboneans are the old imperial British aristocracy in their dying days, even if that was in large part what inspired them. We accept them as their own thing.
At its most base, “caravan cities” should conjure images of caravans AND cities. Something Sartar has a lot of.