Because the philosophers I criticized were/are in fact concerned with science and/or epistemology, and did/do a bad job at it. I'm not making a critique of philosophy as a whole; this isn't a deGrasse Tyson-style "just do science" point that I'm making. My point is that philosophers do try to say things about science, and a lot of them do a poor job of it.

Anyway, no, I don't think one can have knowledge of the nature of wisdom be primary; I think that we have to develop that in concert with our ideas about how to understand things (of which science is a part), and if we don't quite have a handle on what wisdom is yet, we may still be able to say, "Well, whatever it is, it certainly isn't that, because the character of that is simply too far removed from anything that we want to call wisdom."

I think idealism, at this point, fits into that category. It might be wise to keep exploring to see what we can get out of it, but it's not wise to accept it unless accepting fantasy is wise, because it doesn't seem distinguishable from fantasy.