I think it's difficult for us to write such things because it's barely been attempted before.
I mean, it's been done before, don't get me wrong, but we don't have much reference; a King Arthur-like protagonist, for example, just comes more naturally to us.
Also how do u feel about a character starting out in a low socioeconomic position and then becoming a noble or the like.
Weeeelllll, to be frank, I don't think people live boring lives in general, and I think the same goes for a lot medieval commoners that have been through strife and fought in their own wars and discovered lands or places in Europe that were new to them.
I'll say this: it's fantasy and it's supposed to be a bit unrealistic and so I don't mind characters rising up and becoming people of renown, respect, and stature, though in all honesty, I like at Rand al-Thor, realize his heritage, and see that he's still very much a noble or has that privilege that serves him well later on.
It is worth mentioning and thanks for bringing this up.
Definitely gives me pause, though I still think I've gotten the overall jive correct: for every Zora Neale Hurston, there's ten GRRMs out there (and I don't mean that in a good way).
I used mods without realizing I was online.