I don't think there is very much
realism, in the literary sense, in RPGing at all. Or at least, I very rarely see it. The closest I've come in my own RPGing (that I can think of) is
a one-shot of Wuthering Heights. And that is far from a simulationist RPG!
I'm not really sure about
naturalism either. If we think of paradigmatically simulationist RPGs such as RQ, RM and C&S, the systems do have a certain deterministic logic to them. But the themes they deal with, and the sorts of outcomes they generate, don't seem particularly naturalistic.
Or consider the patron encounter chart in Classic Traveller. It supports simulationist RPGing, in that it makes system rather than metagame-influenced choice responsible for generating adventure opportunities for the PCs. But the whole notion that retired soldiers and merchants who hang out in starport bars will regularly be approached (like Sam Spade!) by shady characters wanting shady work done doesn't seem that naturalistic to me.
Stepping back a little bit, I would say that the key to purist-for-system is a certain sort of procedure for determining
what happen next. Whereas these literary movements are more about
content, I think. This is why I'm not seeing the suggested fit.