I agree with Marcus's points about the difficulty of insulating economics from facts about psychology and society. This is presumably because economics is supposed to make predictions about the economic behavior of societies. In contrast, most philosophers think very differently about their subject matter. Generally, we take ourselves to be developing theories about certain properties or relations (metaphysical necessity, knowledge, truth, personhood, explanation), with the use of intuitions that we take to be cross-cultural. On the other hand, some of my colleagues think that the assumption that the intuitions we draw on are cross-cultural is false.
I'm not exactly sure how to proceed in philosophy if the intuitions we draw on are culturally relative. I am pretty certain we won't turn to Foucault. One strategy to exploit if, e.g., intuitions about metaphysical necessity turn out to be culturally relative is to appeal to context-dependence. We could say that "is metaphysically necessary" picks out different properties relative to different contexts of use, and what we philosophers are doing is investigating what they all have in common (this is actually somewhat similar to a move made by David Lewis to accommodate the apparent context-sensitivity of essentialist claims). Anything to avoid Foucault.
UPDATE: Any late-night generalization about what philosophers do turns out to be problematic. My colleague Barry Loewer remarks that I have "overstated the importance of intuitions...at least in some quarters of analytic(?) philosophy." According to Barry, "In philosophy of science intutions - and particularly whether they are cross-cultural- have very little to do with whether e.g. absolute or relational accounts of space are better interpretations of GTR, or with whether statistical mechanics can ground temporal asymmetries etc. I don't mean that the beliefs we have about the world, e.g. that there are temporal asymmetries and their nature are irrelevant. They aren't but I wouldn't call these beliefs 'intuitions.' Even some places where philosophers appeal to intutions, e.g. in disputes between Humean and Governing conceptions of laws (or views about objective chance), they are overrated. Same for counterfactuals and causation. The alternative is to get clear about the role of a certain concept e.g. law, in scientific theorizing. Our intuitions may conflict with an account may tell us something about our psychology, or the cultural history, or bad philosophy that helped shape a concept. But they generally won't tell us much about the world."
The topic of the role of intuitions in philosophy is a very important one, and it bears on some of the issues about the nature of philosophical inquiry we've been discussing (especially in the comments about technical vs. humanist philosophy). There is an issue here about when one is appealing to intuitions that tell us about the nature of a concept (and so doing conceptual analysis, which is supposedly bad) and appealing to facts about the property we're investigating, facts that are simply hard to deny (either for scientific or commonsensical reasons). I grant Barry's point that we're sometimes doing the latter when we think we're doing the former. I didn't mean to suggest otherwise.
The central point of my original post was to discuss why it is implausible to expect that culturally shaped facts will enter into philosophical inquiry in certain areas (roughly metaphysics and epistemology, broadly conceived) in such a way that would lead philosophers to incorporate even very good social theory into their explanations. I linked to Stich et. al.'s work on these topics, because if the plausibility of skepticism (or Gettier cases) turns out to be culturally dependent, then social theory would be as good a place as any to look for an explanation.
My suspicion is that, were philosophers to be convinced about the dependence of a certain class of intuitions on social or cultural facts, then we would use that as a reason to abandon in-depth inquiry into the source of those intuitions. An explanation of why American college students find skepticism plausible but South-East Asian college students don't would no longer be philosophical. As my sociologist father used to tell me, as soon as a question becomes interesting it ceases being philosophical.
It's a standard move in philosophy to argue that a certain bit of discourse is context-sensitive, pragmatically shaped, or what have you. This is used to explain apparently conflicting intuitions or beliefs. Where there is an essentially cultural or social explanation, philosophers are less interested in delving further. I'm not saying that this is healthy or correct, but it's generally first our instinct.